Difficulty: Easy
Correct Answer: True
Explanation:
Introduction / Context:
Elementary gas laws describe limiting behaviours of ideal gases under conditions where one macroscopic variable is held constant. When pressure is maintained constant, temperature and volume changes follow a specific proportionality known from Charles’s law.
Given Data / Assumptions:
Concept / Approach:
Charles’s law states that for a fixed mass of an ideal gas at constant pressure, volume is directly proportional to absolute temperature: V ∝ T, or V/T = constant. This is the isobaric gas law and directly governs what happens when you heat a gas without allowing its pressure to change (e.g., a piston that moves freely to keep pressure constant).
Step-by-Step Solution:
Start with ideal-gas equation: pV = mRT.Hold p and mR constant → V = (mR/p) * T.This yields V/T = constant, which is Charles’s law.Thus, heating at constant pressure increases volume proportionally to temperature.
Verification / Alternative check:
On a V–T plot at constant pressure, data lie on a straight line. Practical demonstrations include heated air balloons or piston-cylinder experiments where the piston rises as temperature increases while pressure stays near ambient.
Why Other Options Are Wrong:
Common Pitfalls:
Using Celsius instead of kelvin; proportionality is linear only on an absolute temperature scale.
Final Answer:
True
Discussion & Comments