Question

which gas is a compound?
a air
b carbon dioxide
c nitrogen
d oxygen

Explanation:

A compound is a substance formed when two or more elements chemically combine. Carbon dioxide (\(CO_2\)) is made of carbon and oxygen. Air is a mixture. Nitrogen (\(N_2\)) and oxygen (\(O_2\)) are elements (diatomic molecules of the same element).

Answer:

B. carbon dioxide