Explain where the energy to cook food comes from when a gas stove burns natural gas, CH4, and oxygen, O2.

The energy to cook food on a gas stove comes from a chemical reaction known as combustion. Here's a step-by-step explanation:

1. When you turn on a gas stove, natural gas (methane, CH4) is released.

2. The gas stove also has a spark or pilot light, which is a small flame that is kept burning. This flame provides the activation energy, or the initial energy needed to start the reaction.

3. When the methane comes into contact with the flame, it reacts with the oxygen in the air. This is a combustion reaction, which can be written as follows: CH4 + 2O2 -> CO2 + 2H2O.

4. This reaction is exothermic, meaning it releases energy in the form of heat and light. The heat is what cooks the food.

5. The products of the reaction are carbon dioxide (CO2) and water (H2O), which are released into the air.

So, the energy to cook food on a gas stove comes from the chemical energy stored in the methane gas. This energy is released when the methane is burned in the presence of oxygen.