Two chemical reactions are shown:

Ca (OH) 2 → CaO + H2O

4K + O2 → 2K2O

Which statement is true?

A. Both are synthesis reactions.

B. Both are decomposition reactions.

C. A is a synthesis reaction, and B is a decomposition reaction.

D. A is a decomposition reaction, and B is a synthesis reaction.

Option D, A is a decomposition reaction and B is a synthesis reaction.

Essentially, a decomposition reaction means that molecules split and form new molecules. In this case, Ca (OH) 2 would decompose into CaO and H2O.

As you can guess, synthesis reactions means that molecules combine together. In this case, 4K + O2 reacts together and combines, becoming 2K2O.

-T. B.