Item SB045002: Bubbles of gas forming as a seashell is placed in vinegar is an example of a chemical reaction.

Which of the following is an example of a chemical reaction?

  1. Salt crystals being crushed into a powder
  2. A powder dissolving in hot water to make hot chocolate
  3. The water from sweat evaporating off of your skin and into the air
  4. Proteins from food being broken down into amino acids in your digestive system