Chapter 5

Gas- matter that has no definite shape or volume, takes both the shape and volume of its container

Kinetic Theory of Gases

-states that tiny particles of gases are in constant motion

Basic Assumptions of Kinetic Theory:

1) no attractive or repulsive forces exist between gas particles

-particles are very far apart from one another

-empty space between particles explains gas compressibility

2) gas particles move in constant random motion

3) all collisions between gas particles are perfectly elastic

-during collisions kinetic energy is transferred without loss from one particle to another

-kinetic energy remains constant

Variables Affecting Gases

1) gas pressure (P)- force exerted by a gas per unit surface area of an object, due to collisions of gas particles with an object

barometer and manometer- instruments used to measure pressure

-Pressure can be measured in:

-kilopascals (kPa)

-millimeters of (mm Hg) 1 mm Hg = 1 torr

-atmospheres (atm)

-pounds per square inch (psi)

**101.3 kPa = 760 mm Hg = 1 atm = 14.7 psi

Convert:

A) 3.45atm mm Hg and kPa

B) 893 mm Hg kPa and atm

2) Volume (V)

-amount of space an object occupies

-expressed in Liters (L)

3) Temperature (T)

-how hot or cold something is

-must be expressed in K

4) Amount of Gas (n)

-expressed in moles

**Remember STP (standard temp and pressure)

T= 273 K, 0°C

P= 101.3 kPa, 760 mm Hg, 1 atm