Understanding chemical equations is difficult.

He is an expert in chemical analysis.

Oxygen, which is one of the chemical elements, is necessary for us to breathe.

Understanding chemical equilibrium is very important in understanding chemical reactions.

In this experiment, you can observe a chemical reaction.

This substance undergoes a chemical change when heat is applied.

The use of chemical weapons is prohibited by international law.

I am majoring in biochemistry at university.

My major is chemical engineering.

I am majoring in inorganic chemistry at university.