By what factor does a gas's volume decrease if its pressure doubles at constant temperature?

Question

An ideal gas is kept at constant temperature. By what factor will its volume decrease if its pressure doubles?

Answer choices

1. 2
2. 4
3. 3

Explanation

For a fixed amount of ideal gas at constant temperature, Boyle's law gives p₁V₁ = p₂V₂.

If p₂ = 2p₁, then V₂ = p₁V₁ / (2p₁) = V₁/2. The new volume is half the original volume.