Atmospheric Pressure: Atmospheric pressure is the force exerted by gas molecules in the air as they strike surfaces. It is measured using a barometer, with standard pressure defined as 760 mm Hg (1 atm).

Units of Pressure: Common units include atmospheres (atm), millimeters of mercury (mm Hg), torr, pascals (Pa), and pounds per square inch (psi). Conversion factors: 1 atm = 760 mm Hg = 101325 Pa.

Boyle's Law: At constant temperature, the pressure and volume of a gas are inversely proportional. P1V1=P2V2

Charles' Law: At constant pressure, the volume of a gas is directly proportional to its temperature (in Kelvin). V1T1=V2T2

Avogadro's Law: At constant temperature and pressure, the volume of a gas is directly proportional to the number of moles. V1n1=V2n2

Combined Gas Law: Relates pressure, volume, and temperature for a fixed amount of gas. P1V1T1=P2V2T2

Ideal Gas Law: Relates pressure, volume, temperature, and moles of a gas. PV=nRT where R=0.0821 L·atm/(mol·K).

Problem Solving: Use the appropriate gas law based on which variables are held constant and which are changing. Convert all temperatures to Kelvin and ensure units are consistent.

Sample Calculations: Example problems demonstrate how to use the gas laws to solve for unknowns such as volume, pressure, temperature, or moles, often requiring unit conversions and algebraic manipulation.