Structure 1.5.1: Ideal Gas Model
Ideal gases consist of moving particles with negligible volume and no intermolecular forces.
Collisions between particles are elastic.
Structure 1.5.2: Real Gases vs. Ideal Gases
Real gases deviate from the ideal gas model at low temperatures and high pressures.
Molar volume of an ideal gas is constant at specific temperature and pressure.
Structure 1.5.3: Ideal Gas Equation
The relationship between pressure, volume, temperature, and the amount of an ideal gas is shown in the equation 𝑝𝑉=𝑛𝑅𝑇pV=nRT and the combined gas law 𝑝1𝑉1𝑇1=𝑝2𝑉2𝑇2T1p1V1=T2p2V2.
Constant Random Motion: Gas molecules move in straight lines until they collide.
Elastic Collisions: No energy is lost in collisions.
Negligible Volume: Volume occupied by gas molecules is insignificant compared to the container volume.
No Intermolecular Forces: Ideal gases do not condense into liquids.
Kinetic Energy and Temperature: Kinetic energy of molecules is proportional to Kelvin temperature.
Pressure is inversely proportional to volume at constant temperature.
The SI unit of pressure is the pascal (Pa).
Standard conditions for gases are 0°C (273.15K) and 100.0 kPa.
Deviations at Low Temperature: Reduced kinetic energy causes intermolecular forces to form, making collisions inelastic.
Deviations at High Pressure: The volume occupied by molecules becomes significant, affecting the inverse pressure-volume relationship.
Assumptions and Conditions: Discuss conditions leading to deviations from ideal behavior.
Comparisons: Predict which gases exhibit ideal behavior under different conditions.
Avogadro’s Law: Equal volumes of gases at the same temperature and pressure contain equal numbers of particles.
At STP, the molar volume of an ideal gas is 22.7 dm³ mol⁻¹.
Use the ideal gas equation to determine the molar mass of a gas.
Conduct experiments with butane and analyze data to find molar mass.
Consider sources of experimental error and improvements to methodology.
The combined gas law 𝑝𝑉𝑇TpV remains constant.
The ideal gas equation 𝑝𝑉=𝑛𝑅𝑇pV=nRT uses the gas constant 𝑅≈8.31R≈8.31 JK⁻¹mol⁻