Interactions Between Particles

Phase change: A transition from one state of matter to another

Stronger forces between particles - higher melting and boiling point

Ionic substances

Lattices: rigid frameworks of atoms, molecules or ions

Metallic Substances

• Form lattices of tightly packed atoms

• Electrons move easily between atoms

• Shapes of metals are easily altered

  • Malleable

  • Ductile

Molecular Substances

Forces within molecules: Covalent bonds

Forces between molecules: Intermolecular forces

Covalent Networks and Polymers

Covalent networks: Lattices of covalent bonds that form giant molecules

Polymers: contain long chains of covalently - bonded atoms

Describing Gases

Ideal Gas

1. Volume of particles is much less than container

2. Particles have no attraction for each other

   1. Connects Temp, Vol, Pressure

Pressure

The force that gases exert on their surroundings

Measuring Pressure

Barometer: A device used to measure atmospheric pressure

Gauge Pressure: The difference between the compressed gas pressure and the atmospheric pressure

The Gas Laws

Boyle’s Law

The pressure and volume of a gas are inversely related

When working with Boyle’s law, we can use any units of pressure and any units for volume

Charles Law

At constant pressure, the volume of a gas is directly proportional to its temperature

Absolute value = -273.15 + Celsius = Kelvin

Solving Problems with Charles Law

Temperature = in KELVIN

The Combined Gas Law

The temperature has to be in KELVIN

Avogadro’s Law

If temp and pressure are both constant, the vol of gas is proportional to the number of moles of gas present

The Ideal Gas Law

Mixtures of Gases: Partial Pressures

The pressure caused by one gas in a mixture; Adding up all partial pressures gives the total pressure

Molecular View of the Gas Laws

Diffusion

The spread of particles through random motion

Lighter particles diffuse more quickly

Effusion

The process of a gas escaping from a container

Gas Stoichiometry