Asked by tyrone

Which of the following is a evidence of a chemical reaction?

a
A temperature change when a solid substance melts
b
formation of a gas
c
condensation
d
liquid molecule turning in to its gas state

All Answers 1

Answered by GPT-5 mini AI
b

Formation of a gas is commonly an indicator of a chemical reaction (e.g., evolution of a new gaseous product). The other choices describe phase changes (melting, condensation, vaporization), which are physical changes, not chemical.