Everyday Examples of Heating and Cooling Reactions

Reactions that Release Heat:

1. Burning Fuels

   • When things like natural gas (methane) burn, they give off heat. For instance, if you burn a certain amount of methane, it releases about 890.3 kilojoules of energy.

2. Breathing

   • When our bodies breathe, we take in glucose (a type of sugar) and oxygen. This process creates carbon dioxide and water, and releases about 2870 kilojoules of energy for every molecule of glucose we use.

3. Making Table Salt

   • When sodium and chlorine join together to make table salt (sodium chloride), they release around 411 kilojoules of energy.

Reactions that Absorb Heat:

1. Photosynthesis

   • When plants make their food, they take in sunlight and use it to turn carbon dioxide and water into glucose. This process needs about 2800 kilojoules of energy.

2. Dissolving Ammonium Nitrate

   • When ammonium nitrate is mixed into water, it pulls in heat, making the temperature drop by about 5 degrees Celsius.

3. Baking Soda and Vinegar Reaction

   • When you mix baking soda with vinegar, it takes in heat and the mixture cools down while producing carbon dioxide gas.