A chemist wants to observe the following reaction:

Question

A chemist wants to observe the following reaction:

2H2 + O2 → 2H2O

The chemist is standing inside a room with oxygen in the air and has a balloon filled with hydrogen. The chemist holds a small flame up to the hydrogen balloon. When the balloon pops, the hydrogen explodes in a ball of fire.

explain which part of the reaction is higher in energy (i.e., does it take more energy to break the bonds of the reactants, or is more energy given off when the product bonds are formed?).

Answer 1

The reaction described is an exothermic reaction, meaning that more energy is given off when the product bonds are formed compared to the energy required to break the bonds of the reactants. In this case, the formation of water (H2O) from hydrogen (H2) and oxygen (O2) releases energy in the form of heat and light, which is observed as the explosion and ball of fire when the hydrogen balloon is ignited.