It explains the behavior of gases in terms of motion of their molecules — linking temperature, pressure, and energy of gas molecules.
The pressure exerted by gas molecules due to their motion.
Where:
The average kinetic energy of gas molecules.
Where:
Directly proportional to temperature.
The square root of the average of squared velocities of gas molecules.
Where:
Faster air molecules in a football → more pressure inside.
PYQ Type: Formula identification / units match
Hotter air in a balloon → faster moving molecules.
PYQ Type: Direct formula / value of k
Hot air balloons rise because hot air has faster moving molecules.
PYQ Type: Numerical / formula identification
The ideal gas equation derived from kinetic theory principles.
Where:
This relation is derived from kinetic theory and universally important.
The relationship at constant volume.
Where T is in Kelvin.
Balloon in sun expands as air pressure increases with heat.
PYQ Type: Concept theory MCQ
2021 Shift 2: Value of Boltzmann constant k
2022 Shift 3: Ideal gas equation PV=nRT application MCQ
2023 Dec Shift 1: Pressure-speed relation theory Q
| Formula | Meaning |
|---|---|
| \( P = \frac{1}{3} \rho \bar{c}^2 \) | Pressure due to gas molecules |
| \( KE = \frac{3}{2} k T \) | Average kinetic energy |
| \( c_{rms} = \sqrt{\frac{3 k T}{m}} \) | Root mean square speed |
| \( c_{rms} = \sqrt{\frac{3 R T}{M}} \) | RMS speed alternate |
| \( PV = n R T \) | Ideal gas equation |
| \( \frac{P_1}{T_1} = \frac{P_2}{T_2} \) | Pressure-Temperature relation |
| Concept | GenZ Example |
|---|---|
| Gas pressure rises with temperature | Football in sunlight |
| Hotter air = faster moving molecules | Balloon rises |
| RMS speed increases with T | Faster air molecules at high temp |
| PV=nRT governs gas expansion | Bike tyre bursts in summer |
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