Question

in your lab, the mass of your product is less than the mass of your reactants. you recall that atoms are not created or destroyed in a chemical reaction, they are just rearranged from the reactants to form the products. you are afraid you have misunderstood something, so you ask your teacher for some help. she reminds you that if a chemical reaction is completed in a closed system then the mass will remain constant. but if the chemical reaction happens in an open system the mass may appear to change. what can account for this apparent difference? a the chemical reaction is in a closed system and a gas is being used as a reactant. b the chemical reaction is in an open system and a gas is being released into the atmosphere. c the chemical reaction is in an open system and the reactants are all liquid while the products are solid. d the chemical reaction is in a closed system and the reactants are all solid while the products are liquid.

Explanation:

In an open - system chemical reaction, if a gas is released into the atmosphere, the mass of the products measured will be less than the mass of the reactants because the gas is no longer accounted for in the mass measurement. In a closed - system, mass is conserved as no matter can enter or leave.

Answer:

B. The chemical reaction is in an open system and a gas is being released into the atmosphere.