experiment to verify law of conservation of mass

Conservation of Mass Experiments

Start with reviewing the difference between physical and chemical changes. (Chemical changes include: gas, color change, precipitate, temperature change, or light). Get some play doh and roll it into a ball. Place it on the scale and ask students if they think the mass will change if you change the shape of the play doh. You could also use legos or anything else you have handy.

Once they’ve seen that physical changes don’t cause a mass change, move on to chemical changes. Here are some labs you can use for different grade levels to teach the law of conservation of mass.

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Verify the Law of Conservation of Mass

To verify the law of conservation of mass in a chemical reaction.

What is the Law of Conservation of Mass ? 

In any physical or chemical process, mass always remains conserved. It can neither be created nor destroyed.

Aim of this experiment is to understand and verify the law of conservation of mass.

Here, we will find the law of conservation of mass by mixing barium chloride and sodium sulphate. Let us take a look at this experiment in a virtual lab.

Apparatus Required

• Digital balance
• Two beakers (150 mL)
• One beaker (250 mL)
• Three glass rods

Chemicals Required

• Wash bottle containing distilled water
• Watch glass containing 7.2 g barium chloride dihydrate
• Watch glass containing 16.1 g sodium sulphate decahydrate
• Dissolve the 7.2 g of barium chloride dihydrate in the 150 mL beaker that has 100 mL distilled water.
• A solution of barium chloride was prepared and weighed (107.2 g). 
• Dissolve the 16.1 g of sodium sulphate decahydrate in the 150 mL beaker that has 100 mL distilled water.
• A solution of sodium sulphate was prepared and weighed (116.1 g).
• Pour the two solutions into the 250 mL beaker and mix thoroughly.
• Measure the mass of the 250 mL beaker once the chemical reaction tends towards completion.
• The mass of the products was found to be 223.3 g.
• Compare the total mass of the reactants with the total mass of the products.
• The total mass of the reactants was 223.3 g. Hence, the mass of the reactants is equal to the mass of the products

Precautions

• The pointer of the digital balance should be at zero before taking the measurements.
• The two solutions should be mixed slowly with constant stirring.
• Wear your lab coat and gloves.
• All the pieces of apparatus must be washed with distilled water before the execution of the experiment.
• Avoid skin contact with chemicals.

What is the law of conservation of mass?

Answer : According to this law, in a closed system, mass cannot be created or destroyed; it can only change forms or be transferred between objects.

Who formulated the law of conservation of mass?

Answer: The law of conservation of mass was formulated by Antoine Lavoisier, a French chemist, in the late 18th century.

Does the law of conservation of mass apply to both physical and chemical changes?

Answer: Yes, the law of conservation of mass applies to both physical and chemical changes. In physical changes, the mass of the substances remains the same even though their physical properties change. In chemical changes, the total mass of the reactants equals the total mass of the products.

Which products are formed when an aqueous solution of barium chloride & sodium sulphate is mixed?

Answer: When aqueous solutions of barium chloride & sodium sulphate are combined, they react to form the aqueous solution of sodium chloride & white precipitate barium sulphate. BaCl 2 (aq) + Na 2 SO 4 (aq) ? NaCl (aq) + BaSO 4 (ppt.)

What kind of reaction occurs between silver nitrate and sodium chloride?

Answer: Silver nitrate and sodium chloride are soluble in water. When they are mixed, silver chloride (AgCl) forms an insoluble precipitate, while sodium nitrate (NaNO 3 ) remains dissolved in the solution. So, it is a type of precipitation reaction. AgNO 3 (aq) + NaCl (aq) ? AgCl (s) + NaNO 3 (aq)

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Law of Conservation of Mass

The Law of Conservation of Mass is a fundamental concept in chemistry, stating that mass in an isolated system is neither created nor destroyed by chemical reactions or physical transformations. According to the law, the mass of the reactants in a chemical reaction equals the mass of the products . Further, the number and type of atom s in a chemical reaction is the same before and after the reaction.

Definition and Statement of the Law of Conservation of Mass

The Law of Conservation of Mass was first articulated by Antoine Lavoisier in the late 18th century. It asserts that the total mass of a closed system remains constant over time. This principle is widely applicable in chemical reactions and also applies to other disciplines.

Applicability of the Law

The law holds true in chemical reactions under ordinary conditions. This is because chemical reactions only involve electrons and do not affect the identities of the parts of the atom .

However, the Law of Conservation of Mass does not hold in nuclear reactions, where mass can convert into energy (and vice versa) according to the principle of mass-energy equivalence as proposed by Einstein in the theory of relativity. This conversion occurs in nuclear fission and fusion reactions and some forms of radioactive decay.

Also, the law applies to isolated systems. If matter or energy enters or exits a system, mass may not be conserved.

Historical Overview

The concept of mass conservation dates back to ancient Greece. Mikhail Lomonsov, outlined the principle in 1756. Lavoisier gets credit for formalizing the law in 1773. His work disproved the then-popular theory of phlogiston , a supposed fire-like element released during combustion. Lavoisier demonstrated that combustion results from chemical reactions with oxygen, not from releasing a mysterious substance, and that the mass before and after the reaction was the same.

Examples in Chemical Reactions

Chemical reactions clearly illustrate the Law of Conservation of Mass. Chemists apply the law in balancing chemical equations.

• Combustion: In a simple combustion reaction , such as burning methane (CH₄), the total mass of methane and oxygen equals the mass of the resulting carbon dioxide and water. CH 4​ + 2O 2 ​→ CO 2 ​ + 2H 2 ​O (4 H, 1 C, 4 O atoms on each side of the reaction arrow.)
• Synthesis: When hydrogen and oxygen gases react to form water, the mass of the two gases equals the mass of the water produced. 2H 2 ​+ O 2 ​ → 2H 2 ​O (4 H and 2 O on both sides of the reaction arrow.)

Examples in Organisms

In biological systems, the law applies to metabolic processes. For example, in photosynthesis , plants convert carbon dioxide and water into glucose and oxygen. The total mass of carbon dioxide and water used equals the mass of glucose and oxygen produced:

6 CO 2  + 6 H 2 O → C 6 H 12 O 6  + 6 O 2

On a larger scale, the law applies to the mass of a human body, which encompasses numerous chemical reactions occurring at once. If you maintain a constant weight, the mass you gain from breathing, eating, and drinking equals the mass lost through breathing, perspiration, urination, and defecation.

Examples in Ecosystems

In ecosystems, the law is evident in nutrient cycles, such as the carbon cycle. Carbon atoms are conserved as they move through different components of the ecosystem, including the atmosphere, hydrosphere, lithosphere, and biosphere. For example, the photosynthesis reaction takes carbon from the air and fixes it into a glucose molecule. Photosynthesis does not create mass, nor is any lost in the process.

• Okuň, Lev Borisovič (2009). Energy and Mass in Relativity Theory . World Scientific. ISBN 978-981-281-412-8.
• Pomper, Philip (1962). “Lomonosov and the Discovery of the Law of the Conservation of Matter in Chemical Transformations”. Ambix . 10 (3): 119–127. doi: 10.1179/amb.1962.10.3.119
• Whitaker, Robert D. (1975). “An historical note on the conservation of mass”. Journal of Chemical Education . 52 (10): 658. doi: 10.1021/ed052p658

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The Conservation of Mass

The Law of Conservation of Mass

The Law of Conservation of Mass dates from Antoine Lavoisier's 1789 discovery that mass is neither created nor destroyed in chemical reactions. In other words, the mass of any one element at the beginning of a reaction will equal the mass of that element at the end of the reaction. If we account for all reactants and products in a chemical reaction, the total mass will be the same at any point in time in any closed system. Lavoisier's finding laid the foundation for modern chemistry and revolutionized science.

The Law of Conservation of Mass holds true because naturally occurring elements are very stable at the conditions found on the surface of the Earth. Most elements come from fusion reactions found only in stars or supernovae. Therefore, in the everyday world of Earth, from the peak of the highest mountain to the depths of the deepest ocean, atoms are not converted to other elements during chemical reactions. Because of this, individual atoms that make up living and nonliving matter are very old and each atom has a history. An individual atom of a biologically important element, such as carbon, may have spent 65 million years buried as coal before being burned in a power plant, followed by two decades in Earth's atmosphere before being dissolved in the ocean, and then taken up by an algal cell that was consumed by a copepod before being respired and again entering Earth's atmosphere (Figure 1). The atom itself is neither created nor destroyed but cycles among chemical compounds. Ecologists can apply the law of conservation of mass to the analysis of elemental cycles by conducting a mass balance. These analyses are as important to the progress of ecology as Lavoisier's findings were to chemistry.

Life and the Law of Conservation of Mass

Ecosystems can be thought of as a battleground for these elements, in which species that are more efficient competitors can often exclude inferior competitors. Though most ecosystems contain so many individual reactions, it would be impossible to identify them all, each of these reactions must obey the Law of Conservation of Mass — the entire ecosystem must also follow this same constraint. Though no real ecosystem is a truly closed system, we use the same conservation law by accounting for all inputs and all outputs. Scientists conceptualize ecosystems as a set of compartments (Figure 2) that are connected by flows of material and energy. Any compartment could represent a biotic or abiotic component: a fish, a school of fish, a forest, or a pool of carbon. Because of mass balance, over time the amount of any element in any one of these compartments could hold steady (if inputs = outputs), increase (if inputs > outputs), or decrease (if inputs 2 . Mass balance ensures that the carbon formerly locked up in biomass must go somewhere; it must reenter some other compartment of some ecosystem. Mass balance properties can be applied over many scales of organization, including the individual organism, the watershed, or even a whole city (Figure 4).

Mass Balance of Elements in Organisms

Each organism has a unique, relatively fixed, elemental formula, or composition determined by its form and function. For instance, large size or defensive structures create particular elemental demands. Other biological factors such as rapid growth can also influence elemental composition. Ribonucleic acid (RNA) is the biomolecular template used in protein synthesis. RNA has a high phosphorus content (~9% by mass), and in microbes and invertebrates RNA accounts for a large fraction of an organism's total phosphorus content. As a result, fast-growing organisms such as bacteria (which can double more than 6 times per day) have especially high phosphorus content and therefore demands. By contrast, among vertebrates structural materials such as bones (made of calcium phosphate) account for the majority of an organism's phosphorus content. Among mammals, black-tailed deer ( Odocoileus columbianus ; Figure 6) have a relatively high phosphorus demand due to their annual investment in calcium- and phosphorus-rich antlers. Failure to meet elemental demands can lead to poor health, limited reproduction, and even extinction. The extinction of the majestic Irish Elk ( Megaloceros giganteus ) is thought to have been caused by the shortened growing season that occurred during the last ice age, which reduced the availability of the calcium and phosphorus these animals needed to grow their enormous antlers.

Obtaining the resources required for metabolism, growth, and reproduction is one of the central challenges of life. Animals, particularly those that feed on plants (herbivores) or detritus (detritivores), often consume diets that do not include enough of the nutrients they need. The struggle to obtain nutrients from poor quality diets influences feeding behavior and digestive physiology and has led to epic migrations and seemingly bizarre behavior such as geophagy (feeding on materials such as clay and chalk). For example, the seasonal mass migration of Mormon crickets ( Anabrus simplex ) across western North America in search of two nutrients: protein and salt. Researchers have shown that the crickets stop walking once their demand for protein is met (Figure 7).

The flip side of the struggle to obtain scarce resources is the need to get rid of excess substances. Herbivores often consume a diet rich in carbon — think potato chips, few nutrients but lots of energy. Some of this material can be stored internally, but this is a limited option and excess carbon storage can be harmful, just as obesity is harmful to humans. Thus, animals have several mechanisms for getting rid of excess elements. Excess nutrients are released in feces or urine or sometimes it is respired (i.e., released as carbon dioxide). This release of excess nutrients can influence both food webs and nutrient cycles.

Mass Balance in Watersheds

Ecologists have often used naturally delineated ecosystems, such as lakes or watersheds, for applying mass balances. A forested watershed receives inputs of carbon through photosynthesis, inputs of nitrogen from nitrogen-fixing bacteria, as well as through the deposition of atmospheric nitrogen, inputs of phosphorus from the slow weathering of bedrock, and inputs of water from precipitation. Outputs include gaseous pathways (e.g., H 2 O losses through evapotranspiration, CO 2 production as respiration, N 2 produced by denitrifying bacteria) and dissolved pathways (nutrients and carbon dissolved in stream water). Outputs also include material transport across ecosystem boundaries, such as the movement of migratory animals or harvesting trees in a forest.

The Hubbard Brook Experimental Forest in the White Mountains of New Hampshire, USA, has been the site of ecosystem mass balance studies since the 1960s. This landscape has similar-sized, discreet watersheds drained by streams and underlain by impermeable bedrock. By installing V-notch weirs, investigators could precisely and continuously measure stream discharge. By measuring the concentration of nutrients and ions in stream water, they could quantify the losses of these materials from the ecosystem. After calculating inputs to the ecosystem (by sampling precipitation, dry deposition, and nitrogen fixation), they could also construct mass balances. Additionally, researchers could experimentally manipulate these watersheds to measure the effects of disturbance on nutrient retention. In 1965, an entire experimental watershed was whole-tree harvested, resulting in large increases in nitrate and calcium losses relative to an uncut reference watershed (Figure 8). By studying inputs and outputs, an understanding of the internal functioning of the ecosystem within the watershed was obtained.

Figure 8: An experimental reference watershed at the Hubbard Brook Experimental Forest in the White Mountains of New Hampshire, USA Researchers have manipulated entire watersheds, for example by whole-tree harvesting, and then monitored losses of various elements. The whole-tree harvesting of watershed 2 in 1965 affected the uptake and loss of nutrients and elements within the forest ecosystem and was followed by high loss rates of nitrate, hydrogen ions, and calcium ions in stream waters for several years. (Stream chemistry data were provided by G. E. Likens with funding from the National Science Foundation and The A. W. Mellon Foundation.) © 2011 US Forest Service .

Mass Balance in Human-Dominated Ecosystems

Mass balance constraints apply everywhere, even to highly altered ecosystems such as cities or agricultural fields. Cities import food, fuel, water, and other materials and export materials such as manufactured goods. Cities also produce large quantities of waste products — with solid waste sent to landfills, CO 2 (and other pollutants) produced from the combustion of fossil fuels being released to the atmosphere. Nutrients from sewage and from fertilizer runoff can end up in rivers where they will fertilize downstream aquatic ecosystems.

Human agricultural systems can also be analyzed using a mass-balance, ecosystem approach. Traditional agricultural practices emphasized efficiency, with most production staying on the farm — food for livestock was produced on the farm, food for farmers' families was produced on the farm, and plant and animal waste was composted for use as fertilizer on the farm. As a result, the amount of material cycling within the farm "ecosystem" was large relative to the inputs and outputs to the system (a relatively closed ecosystem). By contrast, modern industrial agriculture emphasizes maximizing yields over efficiency. Farmers import fertilizer in large amounts (often far exceeding the amounts that crops can use) and grow and export commodity crops. Ironically, in these highly open ecosystems (where inputs and outputs can far exceed internal cycling), food for farmers' families must often be imported as well. Highly productive agricultural systems are critical in feeding the world's growing human population, but as many of the ingredients of modern agriculture (e.g., water, petroleum, phosphorus) become increasingly limiting over the next century (due to depleted geologic deposits), we will be faced with the challenge of increasing the efficiency of these systems. Just as the constraints of mass balance provide a useful tool for ecologists in studying natural ecosystems, mass balance also ensures that the increase in human population and material consumption that has characterized the past 200 years cannot continue indefinitely.

References and Recommended Reading

Chapin, F. S. et al . Principles of Terrestrial Ecosystem Ecology . New York, NY: Springer, 2002.

Likens, G. E. & Bormann, F. H. Biogeochemistry of a Forested Ecosystem . 2nd ed. New York, NY: Springer-Verlag, 1995.

Moen, R. A. et al . Antler growth and extinction of Irish Elk. Evolutionary Ecology Research 1, 235–249 (1999).

Sterner, R. W. & Elser, J. J. Ecological Stoichiometry: The Biology of Elements from Molecules to the Biosphere . Princeton, NJ: Princeton University Press, 2002.

Simpson, S. J. et al. Cannibal crickets on a forced march for protein and salt. Proceedings of the National Academy of Sciences of the USA 103, 4152-4156 (2006).

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Wait, Weight, Don't Tell Me!

A simple chemistry experiment—adding baking soda to vinegar—seems to challenge the law of conservation of mass.

Video Demonstration

• Safety goggles
• Baking soda (sodium bicarbonate)
• Vinegar (standard 5% acetic acid)
• Flask or bottle
• Measuring cup
• Balance scale that reads to at least 0.1 gram
• Optional: extra materials to experiment with, such as more balloons, zip-seal sandwich bags, 2-liter plastic bottles, etc.

• Pour about 1/2 cup (120 mL) of vinegar into the bottle or flask.

To begin, carefully put the sealed flask onto the scale and write down its starting weight.

You’re about to tip the balloon’s contents into the flask. What do you think will happen? Will the weight go up, down, or stay the same? Why?

Write down the final weight when the reaction is over.

Surprise—your balloon swelled enormously, but the weight actually dropped.

This result is especially confounding if you happen to be familiar with the law of conservation of mass : In any closed system, mass is neither created nor destroyed by chemical reactions or physical transformations. In short, the mass of the products of a chemical reaction must equal the mass of the reactants.

Did you really just violate the law of conservation of mass? You might be dying to know what’s going on, but wait, weight—why not figure it out for yourself?

The answer is below…but to avoid a spoiler, skip down to the Going Further section before reading on.

Alright, here’s the answer: Besides the chemical reaction, the only thing that changed in your sealed system was the volume . When you added the baking soda to the vinegar, the two combined to make carbon-dioxide gas, which inflated the balloon.

The expansion of the balloon changed the weight of your sealed flask because you and your entire experiment are submerged in a fluid: air.

Just like water, air is a fluid, and fluids buoy up objects. The upward buoyant force on any submerged object is equal to the weight of the fluid displaced by that object—this is known as Archimedes’ principle . By increasing the volume of your sealed flask, you cause it to displace more air, increasing the buoyant force on it and reducing its weight. Here's the thing to remember: Scales measure weight, not mass. The mass stayed the same due to the law of conservation of mass, but because of buoyancy, the weight went down!

Consider possible explanations for the weight change: Did the balloon leak? Did something funny happen to the scale? What else might be going on? Plan an experiment to test your theory, gather equipment, and carry it out.

For an illuminating variation on the original experiment, try combining your chemicals while they’re sealed inside a 2-liter bottle. Getting things to mix only after you’ve sealed the bottle is an engineering design challenge unto itself. Caution: Do not exceed the recommended amounts of 1/2 cup (120 mL) vinegar and 2 teaspoons (10 mL) baking soda.

To confirm Archimedes’ principle, measure the volume of the balloon and use the known density of air (0.001225 g/cm 3 at 15° C at sea level) to calculate exactly the weight of air displaced by your expanding balloon. Does the weight loss of your flask match the theoretical prediction?

This activity is meant to spark more experimentation. Having a variety of supplies on hand will allow for creative investigation into this phenomenon.

This idea was first introduced to us by visiting fellow Eleanor Duckworth of Harvard University.

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Choose Your Test

Sat / act prep online guides and tips, 2 easy examples of the law of conservation of mass.

General Education

Chemistry is an important subject that you’ll definitely need to know if you’re planning to pursue a chemistry or other science major in college. One thing you should be familiar with is the law of conservation of mass.  What is it? And how is it used in chemistry?

Keep reading to learn what the law of conservation of mass is and how it came to be. We will also give you some law of conservation of mass examples to help you understand the concept better.

What Is the Law of Conservation of Mass?

First off, exactly what is the law of conservation of mass? This law states that in a closed system, matter can neither be created nor destroyed—it can only change form.

Put differently, the amount, or mass, of matter in an isolated system will always be constant regardless of any chemical reactions or physical changes that take place. (Note that an isolated or closed system is one that does not interact with its environment.)

This law is important in chemistry, particularly when combining different materials and testing the reactions between them.

In chemistry, the law of conservation of mass states that  the mass of the products (the chemical substances created by a chemical reaction) will always equal the mass of the reactants (the substances that make the chemical reaction).

Think of it as being similar to balancing an algebraic equation. Both sides around an equal sign might look different (for example, 6 a + 2 b = 20), but they still represent the same total quantity. This is similar to how the mass must be constant for all matter in a closed system—even if that matter changes form!

But how does the law of conservation of mass work?

When a substance undergoes a chemical reaction, you might assume that some or even all of the matter present is disappearing, but, in actuality, it's simply changing form.

Think about when a liquid turns into a gas. You might think that the matter (in this case, the liquid) has simply vanished. But if you were to actually measure the gas, you'd find that the initial mass of the liquid hasn’t actually changed.  What this means is that the substance, which is now a gas, still has the same mass it had when it was a liquid (yes—gas has mass, too!).

What Is the History Behind the Law of Conservation of Mass?

Though many people, including the ancient Greeks, laid the scientific groundwork necessary for the discovery of the law of conservation of mass, it is French chemist Antoine Lavoisier (1743-1794) who is most often credited as its discoverer. This is also why the law is occasionally called Lavoisier’s law.

In the late 1700s, Lavoisier proved through experimentation that the total mass does not change in a chemical reaction, leading him to declare that matter is always conserved in a chemical reaction.

Lavoisier’s experiments marked the first time someone clearly tested this idea of the conservation of matter by measuring the masses of materials both before and after they underwent a chemical reaction.

Ultimately, the discovery of the law of conservation of mass was immensely significant to the field of chemistry because it proved that matter wasn’t simply disappearing (as it appeared to be) but was rather changing form into another substance of equal mass.

What Are Some Law of Conservation of Mass Examples?

Law of conservation of mass examples are useful for visualizing and understanding this crucial scientific concept. Here are two examples to help illustrate how this law works.

Example 1: The Bonfire/Campfire

One common example you’ll come across is the image of a bonfire or campfire.

Picture this: you’ve gathered some sticks with friends and lit them with a match. After a couple of toasted marshmallows and campfire songs, you realize that the bonfire, or campfire, you've built has completely burned down. All you’re left with is a small pile of ashes and some smoke.

Your initial instinct might be to assume that some of the campfire's original mass from the sticks has somehow vanished. But it actually hasn’t —i t’s simply transformed!

In this scenario, as the sticks burned, they combined with oxygen in the air to turn into not just ash but also carbon dioxide and water vapor. As a result, If we measured the total mass of the wooden sticks and the oxygen before setting the sticks on fire, we'd discover that this mass is equal to the mass of the ashes, carbon dioxide, and water vapor combined.

Example 2: The Burning Candle

A similar law of conservation of mass example is the image of a burning candle.

For this example, picture a regular candle, with wax and a wick. Once the candle completely burns down, though, you can see that there is definitely far less wax than there was before you lit it. This means that some of the wax (not all of it, as you’ve likely noticed with candles you’ve lit in real life!) has been transformed into gases —namely,  water vapor and carbon dioxide.

As the previous example with the bonfire has shown, no matter (and therefore no mass) is lost through the process of burning.

Recap: What Is the Law of Conservation of Mass?

The law of conservation of mass is a scientific law popularized and systematized by the 18th-century French chemist Antoine Lavoisier.

According to the law, in an isolated system, matter cannot be created or destroyed — only changed.  This means that the total mass of all substances before a chemical reaction will equal the total mass of all substances after a chemical reaction. Simply put, matter (and thus mass) is always conserved, even if a substance changes chemical or physical form.

Knowing this scientific law is important for the study of chemistry, so if you plan to get into this field, you'll definitely want to understand what the law of conservation of mass is all about!

What’s Next?

Are there other science topics you want to review? Then you're in luck! Our guides will teach you loads of useful topics, from how to convert Celsius to Fahrenheit , to what the density of water is , to how to balance chemical equations .

Need help identifying stylistic techniques in a book you're reading for English class? Let our comprehensive list of the most important literary devices lend you a hand!

Hannah received her MA in Japanese Studies from the University of Michigan and holds a bachelor's degree from the University of Southern California. From 2013 to 2015, she taught English in Japan via the JET Program. She is passionate about education, writing, and travel.

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• Classification of Colloids
• Tyndall Effect
• Separation of Mixtures
• How to separate a Mixture of Two Solids?
• Separation by a suitable solvent
• Separation of Mixtures using Sublimation and Magnets
• How to Separate a Mixture of a Solid and a Liquid?
• Filtration: Definition, Process, Diagram and Examples
• Water Purification
• Centrifugation
• How to Separate Cream from milk?
• Difference Between Homogeneous and Heterogeneous Mixture
• Difference Between Compound and Mixture
• Factors affecting Solubility
• Separation by Evaporation
• Crystallization
• Chromatography
• Distillation
• Separation of Mixtures of Two or More Liquids
• Fractional Distillation
• Pure and Impure Substances
• What is an Element?
• Metals, Non-Metals and Metalloids
• Properties of Metals and Non-Metals

Chapter 3: Atoms and Molecules

• Laws of Chemical Combination
• Law of Conservation of Mass

Verification of the Law of Conservation of Mass in a Chemical Reaction

• Law of Constant Proportions
• What is Atom?
• Atomic Mass
• How Do Atoms Exist?
• Cations vs Anions
• What are Ionic Compounds?
• What are Monovalent Ions?
• What are Divalent Ions?
• Trivalent Ions - Cations and Anions
• Polyatomic Ions
• Formulas of Ionic Compounds
• Chemical Formula of Common Compounds
• Molecular Mass
• Mole Concept
• Problems Based on Mole Concepts
• Dalton's Atomic Theory
• Drawbacks of Dalton's Atomic Theory
• Significance of the Symbol of Elements
• Difference Between Molecules and Compounds
• How to Calculate Valency of Radicals?
• What is the Significance of the Formula of a Substance?
• Gram Atomic and Gram Molecular Mass

Chapter 4: Structure of the Atom

• Charged Particles in Matter
• Thomson's Atomic Model
• Rutherford Atomic Model
• Drawbacks of Rutherford's Atomic Model
• Bohr's Model of an Atom
• Valence Electrons
• Mass Number
• Relation Between Mass Number and Atomic Number
• Why do all the Isotopes of an Element have similar Chemical Properties?
• Why Isotopes have different Physical Properties?
• What is Fractional Atomic Mass?
• Radioactive Isotopes
• Discovery of Electrons
• What is a Proton?
• Rutherford's Alpha Scattering Experiment
• Atomic Nucleus
• How did Neil Bohr explained the Stability of Atom?
• Electron Configuration
• Potassium and Calcium - Atomic Structure, Chemical Properties, Uses
• What is meant by Chemical Combination?
• Difference between Electrovalency and Covalency

Law of conservation of mass states that “The mass can neither be created nor destroyed in a chemical reaction” French chemist Antoine Lavoisier was the first to state the law of conservation of mass in his book. There is just a rearrangement in the atoms of substances for the formation of compounds.

In the chemical process, the law of conservation of mass can be understood as the total mass of the reactant at the beginning of the reaction being equivalent to the mass of the product at the end of the reaction. 

Mass reactants = Mass products

Let’s learn about the law of conservation of mass in detail in this article,

What is the Law of Conservation of Mass?

Law of Conservation of Mass is an important law for states that,

“For an isolated system mass can neither be created nor be destroyed but is easily transformed from one form to another”.

Law of conservation of mass in chemistry says the mass of the reactants at the beginning of the reaction is always equal to the mass of the products at the end of the reaction. The law of conservation of mass can easily be understood under two changes,

• Physical Changes
• Chemical Changes

When Matter Undergoes Physical Change

When the matter undergoes physical change the mass of the components as a whole system is always conserved. For example, take a piece of ice and place it in a flask properly close this flask and weigh it. Now, heat the flask gently to melt the ice into water and again weigh it.

Ice → (Heat)→ Water

The weight of the flask for and after heating is the same. This shows that when a matter undergoes physical change its mass is constant.

When Matter Undergoes Chemical Change

When any matter undergoes a chemical change the mass of the system remains unchanged. Swiss Chemist Hans Heinrich Landolt first explained this concept.

We can understand this concept with the help of the following chemical reaction,

NaCl (s) + AgNO 3 (aqueous) →  AgCl (s) + NaNO 3 (aqueous)

In the above chemical reaction sodium chloride reacts with silver nitrate to form silver chloride and sodium nitrate. The mass of the reactants and the mass of the product are the same in the above reaction.

Experimental Verification of Law of Conservation of Mass

The following experiment can be conducted to verify the law of conservation of mass: 

Things Required

Things required to prove the Law of conservation of mass are,

• Barium chloride (BaCl 2 .2H 2 0),
• Sodium sulphate (Na 2 SO 4 .10H2O),
• Two beakers of 100 and 150 ml respectively.
• Physical balance
• Two watch glasses
• Spring balance (0-500 g),
• Polythene bag
• Distilled water
• A glass rod.

The reaction can be visualised as a precipitation reaction, where the insoluble salt separates out as a precipitate. The reaction occurs between the Barium Chloride (BaCl2 2 (aq)) and Sodium Sulphate (Na 2 SO 4 (aq)). Both the compounds are taken in aqueous solutions, that is water is taken as the solvent. This is a kind of double displacement reaction.

The reaction involved is,

BaCl 2(aq) + Na 2 SO 4(aq) ————-> BaSO 4(aq) + 2NaCl (aq)

Rearranging the equation in the iconic form, we get, 

Ba + (aq) + SO 4 2- (aq) —————> BaSO4 (s)

The reactants involved in the reaction are barium chloride and sodium sulphate, whereas the products involved are barium sulphate and sodium chloride.

Now, we know, 

Mass of the reactants (barium chloride + sodium sulphate) = Mass of the products (barium sulphate + sodium chloride)

Steps Involved

Steps involved in the verification of Law of conservation are:

• 50 ml distilled water is taken in two 100 mL beakers.
• Weigh the two taken watch glasses on a physical balance.
• A quantity of 3.6 g of BaCl 2 .2H 2 0 is taken in a watch glass.
• Dissolve the quantity of aqueous solution of barium chloride in 50ml of distilled water. The contents are stored in beaker A.
• 8.05 g of Na 2 SO4.10H 2 O is taken in another watch glass of a definite mass.
• Dissolve the quantity of aqueous solution of sodium chloride in 50ml of distilled water. The contents are stored in beaker B.
• A 150ml beaker is taken and measured using the spring balance. This beaker will contain the final contents and is labelled as C.
• The solutions contained in beakers A and B are combined together through constant stirring using a glass rod.
• A precipitate emerges on the beaker C, owing due to the formation of the compound barium sulphate (BaSO 4 ).
• The total weight of the products can be calculated by measuring the weight of the beaker.
• The masses of the content of the beakers are measured before and after the reaction.

Assumptions: In the case of distilled water, density is assumed to be 1g /cc.

Things to Take Care

Before starting the experiment we should take care of the following things,

• Small quantities of chemicals should be used to perform the reaction.
• Initially, the spring balance pointer should be at zero marks.
• The reading of spring balance is taken only once its pointer is at the rest position.
• The reading of spring balance should be taken when it is placed in a vertical position.
• Precise quantities of the masses mentioned should be taken.
• Solution of BaCl 2 and Na 2 SO 4 should be mixed with constant stirring.

Observations

The following inferences can be drawn from the experiment, 

• Mass of aqueous solution of barium chloride (BaCl 2 ) = 3.6 g
• Mass of BaCl 2 solution = 53.6 g
• Mass of aqueous solution of sodium sulphate (Na 2 SO 4 .10H 2 O) = 8.05 g
• Mass of Na 2 SO 4 solution = 58.05 g
• Mass of 50 ml distilled water = 50.0 g

Calculating the total mass of reactants, we have, 

BaCl 2 + Na 2 SO 4 = 53.6 + 58.05 

                          = 111.65 g

Conclusions

When we compare the mass of reactants with those of products, the two masses are considered to be equivalent. This implies that the observed masses, m 2 = m 3 .  Hence, the law of conservation of mass is preserved. 

Precautions

Following precautions must be taken while performing the experiment.

• Use the weighing machine with caution as it is sensitive to the slightest change.
• Use distilled water to make the solution.
• When solutions X and Y are mixed place the solution in a bottle with a cork.
• While calculating the resultant mass of the product, subtract the mass of the [conical flask + cork].
• The cork is used to prevent the gas, or vapours, from escaping the solution. The law is valid only for closed systems.
• Never taste any chemicals used in the experiment.

Formula of Law of Conservation of Mass

The formula for the law of conservation of mass is expressed in the differential form using the continuity equation in fluid mechanics which is,

∂/∂t (ρ) + ▽(ρv) = 0 where, ρ is the density t is the time v is the velocity ▽ is the divergence

Law of Conservation of Mass Law of Conservation of Energy Law of Conservation of Momentum

FAQs on Law of Conversation of Mass

Question 1: what does the law of conservation of mass state.

The law of conservation of mass states that the total mass of any isolated system is always constant mass can neither be created nor destroyed.

Question 2: Who discovered the law of conservation of mass?

The law of conservation of mass is first proposed by french chemist Antoine Lavoisier in 1789.

Question 3: State the Law of Conservation of Mass and Energy.

Einstein states that there is a direct relation between the mass and energy of any object. He formulated an equation to justify its proof, this equation is called mass-energy equivalence. The equation is written as, E = mc 2 where, E is the energy of the particle m is the mass of the particle c is speed of light

Question 4: Why is there no change in mass during chemical reactions?

In a chemical reaction, atoms of reactants are rearranged to form the product and are neither created nor destroyed. Hence, there is no change in mass in a chemical reaction.

Question 5: Where is the law of conservation applicability found?

Answer: 

Law of conservation of mass can be seen in chemical reactions, like the production of carbon dioxide, or during the process of combustion of wood. It is applicable to all the phenomena occurring in the closed system.

Question 6: Which other reactions are used to display the law of conservation of mass?

Any combination reaction, where the reactants combine to form a product is used to verify law of conservation of mass. For example, the production of water from hydrogen and oxygen molecules.  2H 2 (4g) + O 2 (32g) => 2H 2 0 (36g)

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Conservation of mass in dissolving and precipitation | 11-14 years

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Explore what happens during precipitation reactions and when substances dissolve using this lesson plan with downloadable activities for 11–14 year olds

This simple practical activity challenges students’ thinking about mass conservation when substances dissolve or when chemical reactions produce precipitates. Working in small groups they carry out a simple experiment and agree answers to questions.

Learning objectives

Students will be able to explain that:

• Mass is conserved during dissolving.
• Mass is conserved during a precipitation reaction.
• Whatever change occurs, the total mass of the substances involved does not change.

Sequence of activities

Introduction.

Introduce the topic, and the learning objectives, by explaining to the students that they are going to look at two events which:

• People often explain using different ideas.
• They will come across a lot in chemistry, so they need to understand them correctly.

Activity: stage 1

Give each student the worksheet, ‘Dissolve and precipitate’.

Organise the students into groups of three. Give each group one flask labelled ‘Dissolve’.

Circulate and support with prompts as groups:

• Work on the dissolving task.
• Discuss the results and agree on an explanation.
• Elect a spokesperson to explain their group’s reasoning to the rest of the class.

Allow about 15 minutes for the groups to complete the task.

In a plenary:

• Draw out, in feedback from each group, their understanding that mass is conserved when substances dissolve.

Explain that in the next task they are going to test another event.

Activity: stage 2

Give each group one flask labelled ‘Precipitate’.

• Work on the precipitation task.
• Draw out, in feedback from each group, their understanding that mass is conserved when a precipitate forms.
• Ask students to reflect how their thinking changed while doing the experiments and to write this on the reverse of the worksheets.
• Collect in the worksheets.

In giving written feedback:

• Point out where students’ individual ideas are incorrect.
• Support and encourage students in changing their thinking to a scientifically correct viewpoint.

The idea of mass conservation is central to developing good understanding of chemical reactions. By sharing their ideas in ‘safe’ groups, students can progress towards scientific understanding in a supported way.

Feedback to the class enables the teacher to assess whether groups have understood the key concept.

Written feedback can pinpoint students who still need to change their thinking and encourage those who have developed the correct view.

Practical notes

For the prepared flasks labelled ‘dissolve’ (see ‘health, safety and technical notes’, notes 3 and 4).

• Conical flask, 500 cm 3
• A small tube to fit comfortably inside the flask
• Stoppers to fit the flask tightly
• Water, about 150 cm 3  in the flask
• About 5–10 g of one of these solids in the small tubes: sodium chloride, sugar, copper(II) sulfate (HARMFUL)

For the prepared flasks labelled ‘Precipitate’ (see ‘Health, safety and technical notes’, notes 3 and 5)

• Pairs of solutions at 1 mol dm -3 that form a precipitate on mixing (for example, sodium sulfate / barium nitrate (HARMFUL and OXIDISING), potassium iodide / lead(II) nitrate (TOXIC), ammonium phosphate / calcium chloride (IRRITANT))

Other equipment

• Access to a balance weighing to 0.01 g

Health, safety and technical notes

• Read our standard health and safety guidance .
• It is the responsibility of the teacher to carry out appropriate risk assessments.
• To prepare the flasks, tie the thread around the necks of the small tubes. Ensure that the length of the thread supports the tube in an upright position in the flask, but allows the contents to mix when the flask is tilted without being opened.
• Put the chosen solid into the tube. Put about 150 cm 3 of water in the flask. Use the thread to arrange the prepared tube in the flask so that the contents mix when the flask is tilted. Label the flask ‘Dissolve’.
• Put the chosen solution (10–20 cm 3 ) into the tube. Put the second solution in the flask. Use the thread to arrange the prepared tubes in the flask so that the contents mix when the flask is tilted. Label the flask ‘Precipitate’.

Principal hazard

• Stoppers insecure in flask, leading to spillage.

Alternative strategy

If time and/or resources are short, the teacher can demonstrate the chemical events. Groups can discuss the results and make their predictions as suggested.

The mass values should remain unchanged during dissolving and precipitation. Responses should reflect this.

Primary teaching notes

If you teach primary science, see the guidance below to find out how to use this resource.

Skill development

Children will develop their working scientifically skills by:

• Asking their own questions about scientific phenomena.
• Using a range of scientific equipment to take accurate and precise measurements or readings.
• Using appropriate scientific language and ideas to explain, evaluate and communicate their findings.

Learning outcomes

Children will:

• Observe that some materials will dissolve in liquid to form a solution, and describe how to recover a substance from a solution.
• Demonstrate that dissolving, mixing and changes of state are reversible changes.

Concepts supported

Children will learn:

• That some materials dissolve to form a solution.
• That materials are still present when they have dissolved and that they haven’t disappeared.
• That mass is conserved when dissolving and precipitating.

Suggested activity use

This activity can be used as a whole class investigation into the dissolving and precipitation processes, with children working in small groups to observe and answer the questions given. Alternatively, the activities could be demonstrated by an adult to stimulate discussion and questioning.

Practical considerations

It is important that the key vocabulary ‘dissolve’ and ‘precipitate’ are understood correctly by children in the introduction of this activity.

The ‘Dissolve’ task is more relevant to the primary science curriculum and could be more heavily focused on.

Conical flasks, stoppers and tubes may not be required for this activity if alternatives can be sourced, such as mini pop bottles and clean fromage frais pots.

Dissolve and precipitate activity sheet

Additional information.

This lesson plan was originally part of the  Assessment for Learning  website, published in 2008.

Assessment for Learning is an effective way of actively involving students in their learning.  Each session plan comes with suggestions about how to organise activities and worksheets that may be used with students.

Acknowledgements

V. Barker,  Beyond Appearances : Student’s misconceptions about basic chemical ideas: A report prepared for The Royal Society of Chemistry, London.  London: Royal Society of Chemistry, 2000.

• 11-14 years
• Practical experiments
• Formative assessment 
• Lesson planning
• Quantitative chemistry and stoichiometry
• Physical chemistry

Specification

• The law of conservation of mass states that no atoms are lost or made during a chemical reaction so the mass of the products equals the mass of the reactants.
• Recall and use the law of conservation of mass.
• 1.47 Explain the law of conservation of mass applied to: a closed system including a precipitation reaction in a closed flask
• 1.47a Explain the law of conservation of mass applied to: a closed system including a precipitation reaction in a closed flask
• C5.3.1 recall and use the law of conservation of mass
• C5.2.1 recall and use the law of conservation of mass
• C1.3k recall and use the law of conservation of mass
• C1.3i recall and use the law of conservation of mass
• Many ionic compounds are soluble in water. As they dissolve the lattice structure breaks up allowing water molecules to surround the separated ions.
• (k) chemical reactions as a process of re-arrangement of the atoms present in the reactants to form one or more products, which have the same total number of each type of atom as the reactants
• 1.1 Atomic structure
• 1. Investigate whether mass is unchanged when chemical and physical changes take place.
• 2. Develop and use models to describe the nature of matter; demonstrate how they provide a simple way to to account for the conservation of mass, changes of state, physical change, chemical change, mixtures, and their separation.
• 4. Classify substances as elements, compounds, mixtures, metals, non-metals, solids, liquids, gases and solutions.

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Conservation of Mass Lab: Explained & Answers

• Conservation of Mass Lab: Explained…

The Law of Conservation of Mass is an important principle to the scientific community and the world of chemistry. The objective of this lab was to verify if this law holds true. This law is beneficial in chemistry as it allows us to predict the final products of a chemical reaction. In this lab, we had verified this law by performing a reaction of sodium bicarbonate and acetic acid. This was done in all three trials, wherein each trial the reaction was performed in a different environment. The first time, it was in an open environment, the second time it was sealed and the third time it was sealed with a balloon. The reaction took place in a plastic 300ml juice bottle with 15 g of sodium bicarbonate used in each trial. We measured the mass of the reactants and containers before the experiment and measured the mass of the products and containers at the end of the reaction. If the law of Conservation of Mass holds true, these masses should be the exact same. From our tests, the masses were not the same but very similar, especially in trial #2 where the bottle was sealed with a cap. There was a difference when the bottle was open, signifying that there was a gas produced in the reaction which escaped. From our results, we can verify that the law of conservation of mass holds true while accounting for human error.

Introduction:

Purpose: The purpose of this lab is to verify the Law of Conservation of Mass holds true

Background:

The Law of Conservation of Mass was developed by the french chemist named Antoine Lavoisier, who had a discovery in 1789 that stated, mass is neither created nor destroyed in chemical reactions. This principle suggests that all atoms on earth have cycled through different forms but were never created nor destroyed in that process. If all the reactants and products are taken into account, he discovered that mass is always preserved. Many other scientists have confirmed Lavoisier’s conclusion, and it is now regarded as scientific law.

This means that the mass of the reactants and products of any chemical reaction in a closed system will be the same. The Law of Conservation of Mass is very important to the scientific world as it allows scientists to predict the amount of product that will be made from a reaction. In this lab, we will be looking at the reaction of baking soda (sodium bicarbonate) and vinegar (acetic acid). This reaction is of a household base and acid, which means a neutralization reaction would occur, because of this we can predict a type of salt and water will be created.

Experimental Design

Experimental Question:

How does the final mass of the products compare to the initial mass of the reactants following a chemical reaction in different experimental conditions?

Independent Variable: The independent variable is the environment or system the chemical reaction takes place in.

Dependent Variable: The dependent variable is the mass of products created by the chemical reaction in different experimental environments.

Controlled Variable: The control in this lab was the initial mass of the reactants as the same amount of reactants were used in each trial. (The only difference in mass was the added covers like the bottle cap and balloon in trials 2 and 3)

If the environment of the chemical reaction is changed, then it will have an effect on the final mass of the products, because the Law of Conservation of Mass stipulates that the mass of the reactants must be the same as the mass of the products in a closed system reaction.

Materials Used:

-1 Electronic Balance

-1 100 mL graduated cylinder

-1 Scoopula

-1 Weighing paper

-1 300 mL juice bottle with cap

-1 Graduated cylinder

-25 g Baking soda (in a 100 mL glass beaker)

-60 mL Vinegar (in a 100 mL glass beaker)

-Recorded the mass of the empty juice bottle without the cap, then poured 15mL of vinegar into the juice bottle. Mass of this was recorded

-Weighed 5g of baking soda onto weighing paper, recorded the exact mass

-Placed bottle with vinegar without a cap and the baking soda onto the scaled, the mass was recorded

-The baking soda was poured into the bottle of vinegar, after the reaction died down the mass of the product was recorded

-A burning splint was placed in the opening of the bottle and the observation was recorded

-Recorded the mass of the empty juice bottle with the cap, then poured 15mL vinegar into the juice bottle and the mass was recorded

-5g of baking soda was weighed and recorded

-Tilted the bottle of vinegar and poured the baking soda into the neck of the bottle, the cap was secured to the bottle

-The bottle then went into the upright position allowing for the baking soda to be dropped, the mass of the product was recorded

-Mass of the empty juice bottle without the cap was recorded, 15mL of vinegar was added and the mass was recorded

-5g of baking soda was weighed and recorded, as well as the mass of all the reactant (balloon, baking soda, vinegar)

-The baking soda was administered to the balloon using a scoopula, the balloon was then placed over the opening of the juice bottle (without allowing the balloon to drop any baking soda into the vinegar)

-The balloon was tipped upright in one motion, once the reaction was complete the mass of the product was recorded

Observations

Percentage Error Formula Used

Initial Mass Vs. Final Mass Graph

Discussions:

  Trial 1:

 The baking soda reacted with the vinegar in trial 1, causing the solution to froth and bubble. The reaction was a neutralization reaction since baking soda (sodium bicarbonate) and vinegar (acetic acid) are bases and acids. Sodium carbonate, water, and carbon dioxide were produced as a result of the process. In trial 1, the bottle’s cap was left off. As a result, the gas was able to easily exit the bottle, resulting in a different final mass measurement. We knew that gas was escaping because we could see it and smell it. The law of conservation of mass states that both reactants and products will have the same mass if the reaction is done in a closed system which was not the case in this trial. When we put our burning splint into the beaker it had gone out, signifying there was a gas that put out fires that was created.

Looking back at the hypothesis, we were in a way correct as the results of the products and reactants were very close, but not exactly perfect. This had to be the case as there was gas escaping from the top of the bottle which would mean there was mass that was unaccounted for. Human error also leads to some error in the perfection of the principle of the law of conservation. To make this trial better, an upgrade would be finding a way to have more precise measurements and to trap all the gas that was leaking to get a proper result. Measurements could have been affected by a slight shake or touch of the beakers, as the scales are very sensitive.

  Trial 2:

This trial fixed the problem in the first trial. Having the cap close the bottle, we were able to contain the gas and get a better measurement. By entrapment, we had changed the environment and system the reaction took place in. In this system, all the gas within the bottle would stay there, which led to an increase in pressure as the bottle filled up with CO2. We know this because it became harder to squeeze the bottle and it let out a hiss when the cap opened. The reaction was also more intense as there was more fizzing and bubbling in the bottle. There was also no smell that we could sense which meant our cap was on tight enough to keep most of the air inside.

Analysis:     

This was our most accurate trial as there was the least amount of failure points and this trial had the best way to keep most of the air inside the bottle. The percentage error was only 0.05% which means this trail verified the Law of Conservation of Mass the best out of all trials. A flaw in this trial was that there was an increase in mass on the products side, this would mean that along the way there was a human error that led to this. The reaction had also been more intense which could be due to the extra pressure in the bottle. While this trial had the lowest error percentage, there were some flaws that could be improved, like a better seal on the bottle cap.

This was our least accurate trial as the percentage error was 1.69%. We replaced the bottle cap with a balloon in this experiment, which allows all of the extra air to fill the bottle and shows us how much pressure is within. The balloon began to inflate a few seconds after the baking soda and vinegar were mixed together. The carbon dioxide produced by the process was absorbed by the balloon. On paper, this notion appears to be quite accurate because you are trapping all of the additional CO2, however in practise, this approach has significant drawbacks. The reaction was also not as prominent as the second trial.

As this was our most inaccurate trial according to the Law of Conservation of Mass, there were a few reasons that caused this. The first would be introducing the balloon. This caused two major problems, the first was that there could not be a great seal at the lip of the bottle which would cause gas to leak. The second was that, because the balloon is rubber, a lot of the baking soda stuck to the inside of the balloon and never reacted. To improve this trial I would remove the balloon as a whole and use another means to deposit the baking soda into the vinegar. The hypothesis still holds true and so does the Law of Conservation of Mass, but this trail was not the best method to verify it.

Inquiry and analysis:

Write a balanced chemical equation for the reaction in this lab.

CH3COOH(aq) + NaHCO3(s) → NaC2H3O2(aq) + H2O(l) + CO2(g)

What evidence was there that a chemical reaction occurred?

We can prove that this was a chemical reaction from a few different events that occurred. The first would be the reaction, when the two reactants mixed together, they reacted violently and created a gas which could be smelled and seen by the bubbles. We also know that Vinegar is an acid and baking soda is a base, this means that if these two substances mixed, a neutralization reaction would occur which creates a byproduct of water and a salt.

How did the final mass of the system compare with the initial mass of the system for each trial?

The final masses we got were very close to the initial mass we started with. This means that almost all of the mass was converted into a new form from the chemical reaction. Trial 2 had the smallest difference between the two masses while trial 3 had the most.

Was the law of the Conservation of Mass upheld? Explain.

While it may appear that the Law of Conservation of Mass was not completely held from our experiments, we must consider human error as well as other factors that could have influenced the final result. Overall, our results were remarkably close when we provided the optimal conditions for the least amount of gas to leave. Matter can neither be generated nor destroyed; it only takes on other forms, as it did here. None of the mass was destroyed; instead, it was lost to the atmosphere and was affected by human error. As a result, the Law of Mass Conservation has been upheld and may be demonstrated to be true.

Conclusion:

After finishing this experiment, we can conclude that the Law of Conservation of Mass is in fact true and very helpful to the world of science. This experiment did in fact support our hypothesis as when the environment of the reactions took place in changed, so did the mass of the products. We were surprised that trial 3 with that balloon had such a high failure rate compared to the open system in trial 1.

Much of the difference in masses could be blamed on human error but there were many factors that were out of our control, such as the weather, the condition of the materials, and general ruckus within the science classroom which could cause minor movements and affect the balance readings.

While considering these aspects and their effects on our experiment, we still believe that our hypothesis was correct and that the principle of the Conservation of Mass was upheld. In further research it would be interesting to push the limits of this law and see if it really does hold true for any reaction in this world or is there an expectation we don’t know of.

Bibliography

Sterner, R. (2011). The Conservation of Mass | Learn Science at Scitable . Nature.com. https://www.nature.com/scitable/knowledge/library/the-conservation-of-mass-17395478/

Study.com. (2022). The Law of Conservation of Mass: Definition, Equation & Examples . Study.com. https://study.com/academy/lesson/the-law-of-conservation-of-mass-definition-equation-examples.html#:~:text=The%20law%20of%20conservation%20of%20mass%20is%20very%20important%20to

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• CBSE Study Material

Law Of Conservation Of Mass: Definition, Formula And More

Law of conservation of mass: this article discusses both the laws of chemical combination and dalton’s atomic theory. read the article to find out more. .

What is the Law of Conservation of Mass? 

The law of conservation of mass states that mass can neither be created nor destroyed in a chemical reaction. The law also states that it can be transformed into another form. It was given by Antoine L. Lavoisier in 1789. The law of conservation of mass is one of the laws of chemical combination, the other being the law of constant proportions. 

What is the Formula of the Law of Conservation of Mass? 

The formula of the law of conservation of mass is as follows: 

∂ρ/∂t +⛛(ρv) = 0

ρ = density

v = velocity

What is the Law of Constant Proportions? 

What is dalton’s atomic theory .

It was John Dalton’s atomic theory that provided an explanation for the laws of chemical combination. According to this theory, all matter, whether an element, a compound or a mixture is composed of small particles called atoms. 

The postulates of the theory are as follows: 

All matter is made of very tiny particles called atoms.

Atoms are indivisible particles, which cannot be created or destroyed in a chemical reaction.

Atoms of a given element are identical in mass and chemical properties.

Atoms of different elements have different masses and chemical properties.

Atoms combine in the ratio of small whole numbers to form compounds.

The relative number and kinds of atoms are constant in a given compound.

What is an Atom? 

Atoms are the building blocks of matter and are very small in size. They are the smallest particles of matter. Example- Sodium (Na), Hydrogen (H)etc.

What is Atomic Mass? 

NCERT defines atomic mass as 'the average relative mass of an atom of the element as compared with the mass of an atom of carbon (C-12 isotope)'. 

What is a Molecule? 

A molecule is a group of two or more atoms that are chemically bonded together. Example-two atoms of hydrogen ) and one atom of oxygen react with each other and form one molecule of water. 

Note: All images have been taken from NCERT Class 9 Science textbook. 

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• What is Dalton's atomic theory? + According to this theory, all matter, whether an element, a compound or a mixture is composed of small particles called atoms.
• What is the law of conservation of mass? + The law of conservation of mass states that mass can neither be created nor destroyed in a chemical reaction.
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How will you verify the law of conservation of mass experimentally?

Step 1: definition of the law of conservation of mass the law of conservation of mass states that the total sum of reactants is equal to the total sum of products. step 2: identifying the requirements to verify the law conical flask, cork, small test tube with a thread tied to its end, sodium chloride ( nacl ) solution, silver nitrate ( agno 3 ) solution, weighing scale step 3: procedure to be performed to verify the law weigh the conical flask, cork and test tube take 20g of sodium chloride solution in the flask add 15g of silver nitrate solution to the test tube and lower it into the flask by holding the thread fix the cork tightly on the mouth of the flask to hold the thread tightly, ensure the reactants don't mix weigh the apparatus, subtract the mass of flask, cork and test tube to get the mass of reactants ( x grams) loosen the cork and thread, let the reactants mix results in the formation of a white precipitate of silver chloride and sodium nitrate solution. weigh the apparatus, subtract the mass of flask, cork and test tube to get the mass of products ( y grams) diagram: result: you will observe that the mass of reactants (x) is equal to the mass of products (y) i.e., 35 g. this verifies the law of conservation of mass..

Which of the following reagent is used in the experiment to verify the law of conservation of mass along with sodium chloride?

How can you verify Faraday's First Law of Electrolysis experimentally?

The reaction used in the experiment to verify the law of conservation of masses is included in which of the following categories?

Which type of reaction is being used in the experiment of verifying the law of conservation of mass?