Law of Conservation of Matter Practice Problems

Look at the following chemical equation. 4FeS + 7O2 → 2Fe2O3 + 4SO2 What is true about this chemical equation?

• It is balanced because the mass of the reactants is equal to the mass of the products.

• It is unbalanced because the mass of the reactants is greater than the mass of the products.

• It is balanced because the sum of the coefficients of the reactants is greater than the sum of the coefficients of the products.

• It is unbalanced because the sum of the coefficients of the reactants is greater than the sum of the coefficients of the products.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Sophia performs an experiment in which she adds 10.0 grams of zinc metal to 25.0 grams of bromine. She claims that mass will be conserved during the reaction. Which of the following BEST supports her claim?

• The mass of the final product will be equal to the mass of the zinc metal, 10.0 grams.

• The mass of the final product will be equal to the difference between the two masses, 15.0 grams..

• The mass of the final product will be equal to the mass of the bromine, 25.0 grams

• The mass of the final product will be equal to the total mass of both reactants, 35.0 grams.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Look at the following equation. __Au2O3 → __Au + __O2 In order to follow the law of conservation of mass, this equation must have which set of coefficients, in order from left to right?

• 2, 4, 3

• 1, 3, 1

• 2, 1, 3

• 1, 1, 3

Tags

NGSS.MS-PS1-5

Look at the following equation. __NaCl + __CaF2 → __NaF +__CaCl2 In order to follow the law of conservation of mass, this equation must have which set of coefficients, in order from left to right?

• 2, 1, 3, 1

• 2, 2, 2, 2

• 2, 1, 2, 1

• 1, 3, 1, 3

Tags

NGSS.MS-PS1-5

Look at the following chemical equation. 2H2O2 → 2H2O + O2 Does this equation follow the conservation of mass?

• Yes, because the mass of the reactants is greater than the mass of the products.

• No, because the mass of the reactants is greater than the mass of the products.

• No, because the coefficient of the reactant is less than the coefficient sum of the products.

• Yes, because each atom that is in the reactants is found in the products.

Tags

NGSS.MS-PS1-5

Chemical equations must be balanced because

• the mass of the reactants is always greater than the mass of the products.

• the mass of the products is always greater than the mass of the reactants.

• mass can neither be created nor destroyed.

• mass is determined by a chemical reaction.

Tags

NGSS.MS-PS1-5

Look at the following chemical equation. 4Al + 3O2 → 2Al2O3 What is true about this chemical equation?

• It is balanced because the mass of the reactants is equal to the mass of the products.

• It is balanced because the number of reactants is equal to the number of products.

• It is unbalanced because the mass of the reactants is greater than the mass of the products.

• It is unbalanced because the number of reactants is greater than the number of products

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5

Which of the following is correct about reactions?

• During nuclear reactions, atoms are rearranged and all the atoms present in the reactants are present in the products.

• During chemical reactions, atoms are rearranged and all the atoms present in the reactants are present in the products.

• During chemical reactions, alpha, beta, or gamma radiation is emitted from the nuclei of the atoms taking part in the reaction.

• During chemical reactions, the amount of energy given off is always more than the energy given off in nuclear reactions.

Tags

NGSS.MS-PS1-2

NGSS.MS-PS1-5