Science Assessment

Natural gas is a fossil fuel that is found deep beneath the surface of the earth. It is made mostly of methane. When natural gas is burned, methane reacts with oxygen to form carbon dioxide and water as represented below.

Methane + Oxygen → Carbon dioxide + Water

As methane reacts with oxygen, a flame is observed and the temperature of the surroundings increases.

Which of the following describes how energy is transferred during this reaction and why?

1. Energy is transferred from the surroundings to the methane/oxygen reaction system because the temperature of the surroundings increased.
2. Energy is transferred from the methane/oxygen reaction system to the surroundings because the temperature of the surroundings increased.
3. Energy is transferred from the methane to the surroundings because methane is a fuel that contains energy. Oxygen does not play a role in the energy transfer.
4. Energy is not transferred during this reaction because chemical reactions involve changes in matter, not changes in energy.