Question

What does ${\mathrm{P}}_1{\mathrm{V}}_1{\mathrm{T}}_1$, ${\mathrm{P}}_2{\mathrm{V}}_2{\mathrm{T}}_2$ mean?

Answer 1

The States of Matter-

• Forces between one molecule and another are called intermolecular forces.
• Intermolecular forces hold molecules together and kinetic energy pushes them apart.
• Stronger intermolecular forces favor the liquid or solid state while higher temperature favors the gaseous state.

1. Solid to the liquid – melting point
2. Liquid to gas - boiling point

Gases- The postulates the kinetic molecular theory.

• Molecules are in constant rapid, random motion.
• The average kinetic energy is directly proportional to the Kelvin temperature.
• Molecules collide with each other and the walls of their container but do not lose energy in doing so (perfectly elastic collisions).
• The volume of the molecules is negligible.
• There are no attractive or repulsive forces between the molecules.
• Pressure results from molecular collisions.
• The theory above describes the attributes of an ideal gas.

Pressure- Atmospheric pressure is measured using a barometer.

• You must know this operation.
• $\mathrm{P}$, $\mathrm{V}$ and $\mathrm{T}$ are abbreviations used for Pressure, Volume, and Temperature. 1, 2, 3…. are used in subscripts for the number of gases.
• Pressure in a container is measured with a manometer.
• Units mm Hg = torr atmosphere = 760 torr = atm = 760 mm Hg Gas Laws.
• Boyle’s law- The volume of a gas is inversely proportional to the pressure when temperature and amount of substance are constant ${\mathrm{P}}_1{\mathrm{V}}_1={\mathrm{P}}_2{\mathrm{V}}_2$.
• Charle’s law - The volume of a gas is directly proportional to the temperature when pressure and amount of substance are constant. $\frac{{\mathrm{V}}_1}{{\mathrm{T}}_1}=\frac{{\mathrm{V}}_2}{{\mathrm{T}}_2}$
• Gay-Lussac’s law- The pressure of a gas is directly proportional to the temperature when volume and amount of substance are constant. $\frac{{\mathrm{P}}_1}{{\mathrm{T}}_1}=\frac{{\mathrm{P}}_2}{{\mathrm{T}}_2}$
• Combined gas law: $\frac{{\mathrm{P}}_1{\mathrm{V}}_1}{{\mathrm{T}}_1}=\frac{{\mathrm{P}}_2{\mathrm{V}}_2}{{\mathrm{T}}_2}$