Which fossil fuel has the least amount of carbon dioxide released in the air each year

The correct answer is - natural gas.

The natural gas is the fossil fuel that releases the least amount of carbon dioxide in the atmosphere. It actually releases very little to none. The reason for that is that the natural gas is a fossil fuel which has the methane as its main ingredient. Even when used, it is not causing some serious pollution, instead the pollution comes from not well managed infrastructure and movement from one place to another of the natural gas. The biggest problem, pollution wise, comes from the leaking of the natural gas, when methane is released into the atmosphere.

the potential energy of the reactants is 200j.

from the energy diagram, the energy of the product formed is 350j; this means that, this reaction is an endothermic reaction, because it absorbs energy from its environment.