Gas laws – heating a gas at constant pressure (Charles’s law) State whether the following is correct: “The heating of a gas at constant pressure is governed by Charles’s law.”

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:

• Gas is modeled as ideal (perfect) in the temperature/pressure range of interest.
• Pressure remains constant during heating (isobaric process).
• Amount of gas is fixed (closed mass).

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:

• False or Boyle’s law: Boyle’s law is for constant temperature (pV = constant), not constant pressure.
• Restrictions to monatomic gases or near 0 °C: unnecessary within ideal-gas assumptions.

Common Pitfalls:Using Celsius instead of kelvin; proportionality is linear only on an absolute temperature scale.

Final Answer:True