Science Review

Science Review

PROBLEM SOLVING

Gay-Lussac’s Law- states that the pressure of a fixed mass of a gas at constant volume varies directly with the temperature in Kelvins.

Combined Gas Law- expresses the relationship between pressure, volume, and temperature of a fixed amount of gas.

​V1P1T2= V2P2T1

MULTIPLE CHOICE

Gas Volumes and the Ideal Gas Law- Main Ideas:

• Gases react in whole-number ratios. Gay Lussac stated that at constant temperature and pressure, the volume of gaseous, reactants and products can be expressed as ratio of small whole numbers.

• Equal volumes of gases under the same conditions equal numbers of molecules. Avogadro’s law states that equal volumes of gases at the same temperature and pressure contain equal number of molecules.

Formula: V=kn

• All gases have a volume of 22.4 L under standard conditions.

• In a chemical equation, the coefficients can indicate moles, molecules, or volume.

• Pressure, volume, and temperature are related to the number of moles of a gas. Ideal gas law is the mathematical relationship among pressure, volume, temperature, and the number of moles of a gas.

• The ideal gas law that relates pressure to volume to temperature. Ideal gas constant is R.

Formula: R= PV/nT

Diffusion and Effusion

• The rates of effusion and diffusion for gases depend on the velocities of their molecules.

o Graham law of effusion states that the rates of effusion of gases at the same temperature and pressure are inversely proportional to the square root of their molar masses.

• Diffusion: the movement of particles from regions of higher density to regions of lower density.

• Effusion: the passage of a gas under pressure through a tiny opening.

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