Alison finds the total mass of a sample of baking soda, a balloon, and a glass container with vinegar in it. She adds the baking soda to the vinegar and immediately places the balloon over the mouth of the container. After the reaction is complete, she again finds the total mass of the system. Which statement is true:
1. The mass does not change because chemical changes observe the law of conservation of mass.
2. Mass is gained during the reaction because a chemical change is taking place.
3. Mass is lost during the reaction because the gas is less dense than the baking soda or vinegar.
4. Mass is lost during the reaction because the gas can change in volume but baking soda and vinegar cannot.