Which of the following events are not examples of a chemical reaction?

atoms of gold turning into atoms of iron

conversion of methane, which contains carbon and hydrogen, and oxygen into carbon dioxide and water <<<?

the rusting of iron in a humid atmosphere

decomposition of water into hydrogen and oxygen gases

All of the examples given are examples of a chemical change. Methane contains carbon and hydrogen but no oxygen.

ththe rusting of iron in a humid atmosphere

decomposition of water into hydrogen and oxygen gases

I thought those two are also chemical?

What part of ALL did you not understand? All four examples you listed are examples of a chemical change. The question, as stated, has no correct answer listed.

Thats why i need help with this problem.

the only choices i have is these four.

atoms of gold turning into atoms of iron

conversion of methane, which contains carbon and hydrogen, and oxygen into
carbon dioxide and water

the rusting of iron in a humid atmosphere

decomposition of water into hydrogen and oxygen gases

The correct answer is "none of these".

The correct answer is "atoms of gold turning into atoms of iron"