Question

select the correct answer.
a scientist conducts a chemical reaction. at the beginning of the reaction, she combines 5.4 grams of the first reactant and 6.3 grams of the second reactant. she runs the reaction in a closed chamber and heats only the reaction. a small amount of gas is produced. what can you conclude about the total mass of the substances present when the reaction is complete?

the mass is greater than 11.7 grams because heat adds additional mass.

the mass is greater than 11.7 grams because a new product was made.

the mass equals 11.7 grams because the system is closed.

the mass is less than 11.7 grams because a gas was produced.

Explanation:

The law of conservation of mass states mass is conserved in a closed system. Initial mass: 5.4g + 6.3g = 11.7g. Closed chamber retains all products, so total mass remains 11.7g. Heat and new products don't add mass; gas production in closed system doesn't reduce mass.

Answer:

C. The mass equals 11.7 grams because the system is closed.