AP CHEMISTRY UNIT 3 - - weaker than covalent bonds, but can be in the...

AP CHEMISTRY UNIT 3

1. metallic atomic solids:

• weaker than covalent bonds, but can be in the low end of covalent bonding
• lattice points occupied by metal atoms
• held together with metallic bonds
• soft to hard, low to high melting points
• good conductors of heat and electricity

2. molecular crystals:

• lattice points occupied by molecules
• held together by IMFs
• soft, low melting point (lowest)
• poor conductor of heat and electricity

3. network solids:

• diamond/graphite
• silicon dioxide/nitride
• boron nitride

4. pressure equation: P=force/area

5. barometer: measures air pressure

6. Boyle's Law: P1V1=P2V2

7. Charles' Law: V1/T1=V2/T2

8. Gay-Lussac's Law: P1/T1=P2/T2

9. Combined Gas Law: P1V1/T1=P2V2/T2

10. Avogadro's Law: V1/n1=V2/n2

11. Ideal Gas Law: PV=nRT

• Dalton's Law of Partial Pressures: the total pressure of a mixture of gases is equal to the

sum of the pressures of all the gases in the mixture 1 / 2

• mole fraction: ratio of the number of moles of a given component in a mixture to the total

number of moles in the mixture (does not change with temp)

• kinetic molecular theory of gases: a model used to explain the behavior of (ideal) gases

• volume of individual particles is negligible because particles are so small
• particles are in constant motion (cause pressure)
• gas molecules do not exert attractive or repulsive forces on each other

• Maxwell-Boltzmann distribution: shows the spread of energies that molecules of gas or

liquid have at a particular temperature

• diffusion: the process by which molecules move from an area of higher concentration to an

area of lower concentration

• effusion: a process by which gas particles pass through a tiny opening into a chamber
• Graham's law of effusion: - states that the rate of effusion for a gas is inversely proportional

to the square root of its molar mass

• Henry's Law: the solubility of a gas in a liquid is directly proportional to the partial pressure

of that gas on the surface of the liquid

20. solution: a homogeneous mixture of two or more substances

21. solute: the substance that is dissolved; present in smaller amounts

• intermolecular forces: forces of attraction between molecules (not chemical bonds)

23. van der Waals forces: intermolecular forces of attraction

• dipole-dipole interactions: - molecules have permanent dipoles attracted to one another
• positive end of one attached to negative end of the other
• these forces matter when molecules are close to each other
• more polar -> higher boiling point
• permanent dipole: permanent separation of electrical charge in a molecule due to unequal

distributions of bonding and/or lone pairs of electrons

26. hydrogen bonding: - H is bonded to N,O, or F

• bonding caused by high electronegativity and small size of N, O, and F
• London dispersion forces: - attractions between an instantaneous dipole and an induced

dipole

• present in all covalent molecules, weakest bond
• / 2