Question

which substance is a vapor at room temperature and standard atmospheric pressure?
a) helium
b) oxygen
c) gasoline
d) carbon dioxide

Explanation:

A vapor is a substance in the gas - phase that is normally a liquid or solid at room temperature and standard atmospheric pressure. Helium, oxygen, and carbon dioxide are gases at room temperature and standard pressure and are not vapors as they do not have a liquid or solid state under these conditions. Gasoline is a liquid at room temperature and standard pressure but has a significant vapor pressure, so some of it exists as a vapor.

Answer:

C. gasoline