1. Chapter 11 – Liquid and Intermolecular Forces

2. States of Matter
Solid- matter that can not flow (definite shape) and has definite volume
Liquid- definite volume but takes the shape of its container and can flow
Gas- a substance without definite volume or shape and can flow

3. States of Matter Solid Liquid Gas Definite Volume? Definite Shape?
Will it Compress?
Solid
Liquid
Gas

4. Intramolecular & Intermolecular Forces
Intramolecular forces hold atoms together in a molecule.
Intermolecular forces are attractive forces between molecules
Ex: 41 kJ vaporizes 1 mole of water (Inter)
Ex: 930 kJ to break all O-H bonds in 1 mole of water (Intra)
Intermolecular forces are weaker than intramolecular forces
Many physical properties can be measured by intermolecular forces like boiling points, melting points, viscosity, surface tension, and capillary rise.

5. Types of Intermolecular Force
Dispersion Forces (or London dispersion forces): Attractive forces that arise as a result of temporary dipoles induced in atoms or molecules.
Ex: All molecules
Dipole–Dipole forces: Attractive forces between polar molecules.
Ion–Dipole forces: Attractive forces between an ion and polar molecule

6. Practice Questions
Ex: What type(s) of intermolecular forces exist between each of the following molecules?
CH4
SO2
CH3Cl
NaCl (aq)
CS2

7. Hydrogen Bonding
Hydrogen bonding is a special dipole–dipole interactions between the H atom when it is bonded to N, O, or F.
Hydrogen bonding arises in part from the high electronegativity of nitrogen, oxygen, and fluorine.

8. Properties of Liquids
Cohesion is the intermolecular attraction between like molecules. Ex: Mercury has stronger cohesive forces with itself (upper meniscus). Adhesion is an attraction between unlike molecules (lower meniscus). Ex: Water has stronger adhesive forces with glass Viscosity is a measure of the fluid’s resistance to flow. Molecules with strong intermolecular forces have a high viscosity.

9. Properties of Liquids
Surface tension is the amount of energy required to stretch or increase the surface of a liquid by a unit area.
Molecules with strong intermolecular forces have high surface tension

10. Phase Change of Water Liquid Gas Solid melting vaporization freezing
condensation

11. Heating Curve for H2O Gas Temperature → Liquid Solid Heat Supplied →
Vaporization
Condensation
Temperature →
Melting
Freezing
Heat Supplied →

12. Vapor Pressure
The boiling point of a liquid is the temperature at which its vapor pressure equals atmospheric pressure.
The normal boiling point is the temperature at which its vapor pressure is atmospheric pressure (1 atm).

13. Phase Diagram of Water
A phase diagram summarizes the conditions at which a substance exists as a solid, liquid, or gas. The melting, boiling, and sublimation points are at different pressures.

14. Phase Diagram of Carbon Dioxide
CO2 cannot exist in the liquid state at pressures below atm (triple point)
CO2 sublimes at normal pressures.