Which of the following statements is true about density comparisons between oil and natural gas?

• A. Oil is denser than natural gas
• B. Natural gas is denser than oil
• C. They have the same density
• D. Density cannot be determined

Answer: (A)

Density tells us how much mass sits in a given volume. Under normal conditions, a liquid like oil is much denser than a gas like natural gas. Oil typically has a density around 0.8–0.95 g per cubic centimeter, while natural gas (mostly methane) is about 0.7 g per liter at standard conditions, which is roughly 0.0007 g per cubic centimeter. So in the same volume, oil would weigh hundreds to thousands of times more than natural gas. That’s why the statement that oil is denser than natural gas is true. Natural gas isn’t denser than oil, and the densities of gas and liquid aren’t the same under these conditions.