She overreacted to his words.

Nuclear reactions are used for mass production of energy.

I was surprised by his overreaction.

He is spending money unreasonably.

I apologize for not contacting you for a long time.

This reaction occurs through a chemical process.

He is an excellent chemist who made many discoveries.

He is an expert in petrochemistry.

It's difficult to decipher this chemical equation.

Understanding chemical equations is difficult.