30 points for correct answer As a part of an investigation, students combined substances in a beaker to observe chemical reactions. They performed two procedures. They measured the mass of each substance before and after each reaction. The table shows their observations.

Procedure 1: mass of reactants: 100g Mass of products: 97.5g
Procedure 2: mass of reactants: 100g Mass of products: 102.5g

What likely explains these changes in mass?
A) Procedure 1: The reactants were liquids with different densities.
Procedure 2: The reactants were combined into only one product.

B) Procedure 1: One of the products was a gas that escaped into the air.
Procedure 2: A gas from the air reacted with one of the other reactants.

C) Procedure 1: All the reactants were liquids that evaporated.
Procedure 2: A gas was formed as one product, and it escaped into the air.

D) Procedure 1: One of the reactants was converted to thermal energy.
Procedure 2: All the products were liquids.