Gaseous State of Matter — A/L Chemistry

What must I remember about Gaseous State of Matter?

• The kinetic molecular theory explains gas behavior: particles are in constant random motion, have negligible volume compared to container volume, and exert pressure via elastic collisions.
• Gas laws relate state variables: Boyle's law (P ∝ 1/V at constant T), Charles's law (V ∝ T at constant P), and Avogadro's law (V ∝ n at constant P, T).
• Dalton's law of partial pressures: total pressure in a non-reacting gas mixture equals the sum of partial pressures (P_A = x_A × P_total, where x_A is mole fraction).
• Real gases deviate from ideal behavior at high pressure (molecular volume becomes significant) and low temperature (intermolecular attractions become significant).
• Graham's law of diffusion: the rate of effusion/diffusion of a gas is inversely proportional to the square root of its molar mass: Rate₁ / Rate₂ = √(M₂ / M₁).

Test yourself (1 minute)

1. Gas collected over water

   P_drygas = P_total - P_H2O(vapor pressure at that temperature).

2. van der Waals equation

   (P + an²/V²)(V - nb) = nRT, where 'a' corrects for intermolecular attractions and 'b' corrects for finite molecular volume.

3. Under what conditions does a real gas come closest to ideal behaviour?

   Real gases approach ideal gas behavior under conditions of low pressure and high temperature.

Practise Gaseous State of Matter questions today

Source: NIE G.C.E. (A/L) Chemistry Syllabus (Unit 4)

What comes next?

Next in the syllabus

Where does Gaseous State of Matter fit in the syllabus?

Grade 12 · Term 2