Chemistry - Chapter 12

Vocabulary

Barometer

A device for measuring atmospheric pressure. It was invented in 1643 by Evangelista Torricelli.

mmHg

millimeters of mercury; unit for pressure equivalent to torr

torr

unit for pressure equivalent to mmHg

standard atmosphere (atm)

a unit of measurement of pressure equal to 760 mmHg/torr, 101,325 Pa, and 14.69 psi.

Pascal (Pa)

SI unit of measurement for pressure equal to one Newton per square meter. 101,325 pa also equals 1 standard atmosphere.

Boyle's Law

The volume of a given sample of gas at constant temperature varies inversely with the pressure; P1V1 = P2V2

Absolute Zero

Theoretical lowest temperature possible, defined as 0 Kelvin or -273°C (possible lowest since volume cannot be negative).

Charles's Law

The volume of a given sample of gas at constant pressure is directly proportional to the temperature in Kelvins; V1/T1 = V2/T2

Avogadro's Law

Equal volumes of gases at the same temperature and pressure contain the same number of (directly proportional to) particles (atoms or molecules); V1/n1 = V2/n2; It was postulated in 1811 by Amadeo Avogadro.

Universal gas constant

The combined proportionality constant in ideal gas law; 0.08206 Latm/molK or 8.314 J/Kmol

Ideal Gas Law

An equation relating to the properties of an ideal gas, expressed as PV=nRT

Ideal Gas

Hypothesized gas that exactly obeys the ideal gas law. A real gas approaches ideal behavior at high temperature and/or low pressure

Combined Gas Law

Simplified gas law equation where moles are constant; P1V1/T1 = P2V2/T2

Partial Pressure

The independent pressure exerted by different gases in a mixture; the pressure that the gas would exert if it were alone in a container.

Dalton's law of Partial Pressures

For a mixture of gas in a container, the total pressure exerted is the sum of the pressures that each gas would exert if it were alone.

P(total) = P1 + P2 + P3…..

Kinetic Molecular Theory

A model that assumes that an ideal gas is composed of tiny particles (molecules) in constant motion. It attempts to explain the behavior of an ideal gas.
1) Gases consist of tiny particles
2) The volume of these particles could be assumed to be negligible.
3) Particles are in constant motion, colliding with the walls of the container which causes pressure.
4) Particles do not attract or repel each other.
5) average kinetic energy is directly proportional to K temp. of the gas.

Molar Volume

The volume of one mole of an ideal gas; equal to 22.42 L at standard temperature and pressure

Standard Temperature and Pressure (STP)

The condition 0°C and 1 atmosphere of pressure