Question

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

Explanation:

A vapor is a substance in the gas - phase at a temperature where it can also exist in the liquid or solid - phase. Gasoline is a liquid at room temperature and standard atmospheric pressure. Carbon dioxide, oxygen, and helium are gases under these conditions, but they do not have a liquid or solid phase at these conditions under normal circumstances. However, the term "vapor" is often used more loosely for substances that can evaporate easily. Among the options, gasoline can form a vapor as it evaporates.

Answer:

A. gasoline