07/14 Gases and Molecular Motion Free Online FlashCards

What four variables primarily describe gas behavior?

Pressure, volume, amount, and temperature are the four principal variables used to describe measurable gas behavior.

How is pressure defined?

Pressure is force per unit area: P = F/A. Gas pressure results from particles colliding with container surfaces.

Why must gas-law temperatures be in kelvins?

Convert Celsius to kelvins with T(K) = T(°C) + 273.15. Gas-law ratios require absolute temperature.

What relationship does Boyle’s law describe?

At constant temperature and amount, pressure is inversely proportional to volume: P₁V₁ = P₂V₂.

What relationship does Charles’s law describe?

At constant pressure and amount, volume is directly proportional to absolute temperature: V₁/T₁ = V₂/T₂.

What relationship does Amontons’s law describe?

At constant volume and amount, pressure is directly proportional to absolute temperature: P₁/T₁ = P₂/T₂.

What relationship does Avogadro’s law describe?

At constant pressure and temperature, volume is directly proportional to amount: V₁/n₁ = V₂/n₂.

What is the combined gas law?

For a fixed amount of gas changing between two conditions, P₁V₁/T₁ = P₂V₂/T₂.

What is the ideal gas equation?

The ideal gas equation is PV = nRT, where P is pressure, V volume, n moles, T kelvins, and R the gas constant.

How are gas density and molar mass related?

Gas density is d = MP/RT, and molar mass can be found from M = dRT/P.

What does Dalton’s law state?

Dalton’s law states that total pressure equals the sum of partial pressures: Ptotal = P₁ + P₂ + P₃ + …

How is dry-gas pressure found over water?

For gas collected over water, subtract water-vapor pressure: Pdry gas = Ptotal − PH₂O.