The video tutorial explains the conservation of mass, a fundamental principle stating that the mass of reactants equals the mass of products in a chemical reaction. It illustrates this concept with examples, such as the reaction between methane and oxygen, and discusses mass-mass conversions. The video also covers complete conversion, limiting reagents, and practical applications, emphasizing that mass is conserved when all reactants are converted to products.

What does the law of conservation of mass state?

• Mass of reactants is greater than mass of products.

• Mass of reactants is less than mass of products.

• Mass of reactants is equal to mass of products.

• Mass of reactants is unrelated to mass of products.

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NGSS.MS-PS1-2

NGSS.MS-PS1-5

Why is the mass of reactants equal to the mass of products?

• Because new atoms are formed.

• Because energy is created.

• Because matter can neither be created nor destroyed.

• Because atoms are destroyed.

Tags

NGSS.MS-PS1-5

In a balanced chemical reaction, what must be the same on both sides?

• Number of molecules.

• Number of compounds.

• Number of atoms of each element.

• Number of ions.

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NGSS.MS-PS1-5

What happens to the mass in a closed reaction flask during a reaction?

• It fluctuates.

• It remains the same.

• It decreases.

• It increases.

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NGSS.MS-PS1-5

If you know the amounts of reactants, what can you determine?

• The color of the products.

• The amount of products.

• The speed of the reaction.

• The temperature of the reaction.

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NGSS.MS-PS1-5

What must be true for the conservation of mass to apply in a reaction?

• No reactants must be converted to products.

• Some reactants must be converted to products.

• All reactants must be converted to products.

• Only one reactant must be converted to products.

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NGSS.MS-PS1-5

How can you find the amount of an unknown reactant if you know the amount of products?

• By guessing.

• By observing the color change.

• By using the conservation of mass.

• By measuring the temperature.

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NGSS.MS-PS1-5

What is a limiting reagent?

• A reagent that is partially used.

• A reagent that is completely used up.

• A reagent that is in excess.

• A reagent that does not react.

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NGSS.MS-PS1-5

What happens to the excess reagent in a reaction?

• It turns into energy.

• It forms new compounds.

• It remains in the reactants and products.

• It disappears.

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NGSS.MS-PS1-5

When can you use the law of conservation of mass to determine missing amounts?

• When the problem does not provide any information.

• When the problem states the reactants do not react.

• When the problem states the reactants react partially.

• When the problem states the reactants react completely.

Tags

NGSS.MS-PS1-5