Gases- REGENTS

Postulate 4

• Gas particles have no forces of attraction between them

• Gas particles are attracted to each other

• Gas particles have strong intermolecular forces

• Gas particles occupy a fixed volume

Avogadro's Hypothesis

• Samples of gas that have the same temperature and the same pressure that occupy the same volume have the same amount of molecules.

• All gases at the same temperature and pressure have the same density.

• The volume of a gas is directly proportional to the number of moles at constant temperature and pressure.

• Gases consist of tiny particles that are in constant motion.

Ideal Gas

• A gas that follows all parts of the kinetic molecular theory

• A gas that has a fixed volume and shape

• A gas that does not obey the laws of thermodynamics

• A gas that is composed of large molecules

Real Gas

• a gas that follows all parts of the kinetic molecular theory

• a gas that does not follow all parts of the kinetic molecular theory

• a gas that behaves ideally at high pressures

• a gas that is composed of only one type of molecule

Volume vs. Temperature

• 
• Volume decreases with temperature in gases.

• Volume is independent of temperature in solids.

• Volume decreases with temperature in liquids.

Pressure vs. Volume

• 
• Pressure and volume are directly proportional.

• Volume is independent of pressure.

• Pressure decreases as volume increases.

Combined Gas Law

• 
• P1V1/T1 = P2V2/T2

• P1V1 = P2V2

• PV = nR

Pressure vs. Temperature

• 
• Pressure decreases with temperature in gases.

• Pressure and temperature are unrelated.

• Pressure is always higher than temperature.

Postulate 3

• Gas molecules are spread so far apart that the volume of each individual particle is negligible

• Gas molecules are tightly packed and have a significant volume

• Gas molecules are in constant motion and have no volume

• Gas molecules are only found in solid form

Gases behave most like an ideal gas under the following conditions:

• high temperature

• low pressure

• high pressure

• low temperature