If both volume and the absolute temperature of a confined gas are doubled, the pressure will

If both volume and the absolute temperature of a confined gas are doubled, the pressure will

• A. Increase
• B. Decrease
• C. Not change
• D. Double

Answer: (C)

When you keep a fixed amount of gas in a container, pressure is tied to temperature and volume through P ∝ T/V (from P = nRT/V for an ideal gas). If the absolute temperature is doubled, the numerator doubles; if the volume is doubled, the denominator doubles. Since both changes happen at the same time, they cancel each other out, leaving P unchanged. So the pressure stays the same. This assumes ideal-gas behavior, which is the usual context for these questions. If only temperature increased, pressure would rise; if only volume increased, pressure would fall; with both doubled, those effects cancel.

When you keep a fixed amount of gas in a container, pressure is tied to temperature and volume through P ∝ T/V (from P = nRT/V for an ideal gas). If the absolute temperature is doubled, the numerator doubles; if the volume is doubled, the denominator doubles. Since both changes happen at the same time, they cancel each other out, leaving P unchanged. So the pressure stays the same. This assumes ideal-gas behavior, which is the usual context for these questions. If only temperature increased, pressure would rise; if only volume increased, pressure would fall; with both doubled, those effects cancel.