CHEM 301 Unit 3

ideal gas law

PV=nRT

boyle’s law

P1V1=P2V2

charles’ law

V1/T1=V2/T2

avogadro’s law

V1/n1=V2/n2

gay lussac’s law

P1/T1=P2/T2

pressure-moles relationship

P1/n1=P2/n2

combined gas law

P1V1/T1=P2V2/T2

density

ρ=mass/volume

density derived from ideal gas law

ρ=PMW/RT

molecular weight

MW=m/n

at STP (P=1 atm and T=273 K)

22.4 L/1 mol

at T=300 K

RT=25

partial pressure

Ptot=P1+P2+P3…

gas reaction stoichiometry

1. convert g to moles

2. find limiting reactant (doesn’t let full combustion reaction)

3. add moles of products that can be made

4. also add moles from reactants that are not combusted

5. convert using standards or ideal gas equation

change in volume

1. use given volume to find volume of others based on the ratio of their moles

2. Vproducts-Vreactants=change in V

kinetic molecular theory

1. simple, hard spheres

2. infinitely small compared to volume of a system (no volume)

3. elastic collisions, no sticking (no IMFs) or react

4. KE ↑ T ↑

5. m ↑ v ↓

6. velocity in a vacuum > velocities when diffusing

general combustion reaction

reactants: hydrocarbon CxHy + oxygen _O2 → carbon dioxide _CO2 + water _H2O

graham’s law for rate of effusion/diffusion at same temp

v1/v2=√(MW2)/(MW1)

maxwell-boltzmann distributions of gases: m constant, T changes

highest to lowest: Tlow, Tmed, Thigh

maxwell-boltzmann distributions of gases: T constant, m changes

mlarge, mmed, msmall

ideal gas conditions

P and n ↓, V and T ↑

“a” term

stickiness or IMFs; bigger means it’s less ideal

“b” term

size (MW); bigger means it’s less ideal

ideal gases

small and nonpolar (low IMFs or a, small or b)

non-ideal gases

large IMFs (high a) or large gases (high b)

increasing strength in IMFs

dispersion<dipole-dipole<h-bonding<ion-dipole

ionic

dominant in salts (metal and nonmetal pair) with a full formal charge

ionic relationships

increase with LE (charge, small atomic radii)

dipole-dipole

permanent dipoles (polar compounds)

dipole-dipole relationships

increase with change in EN

dispersion

occur from instantaneous dipoles formed by asymmetrically distributed e- (nonpolar)

molecules that have dispersion forces

all molecules have dispersion forces because they all have e-

dispersion relationships

increase with MW

more branching

weaker IMFs (dispersion)

more linear

stronger IMFs (dispersion)

h-bonding ranking

difference in EN, # of H-bonds

h-bonding exceptions

NH3<H2O<HF

properties of liquids direct to IMFs

boiling point, viscosity, surface tension, melting point, capillary action, ΔHvap, non-ideality

boiling point

bulf phenomenon where atmospheric pressure=vapor pressure of the liquid so the liquid becomes vapor

viscosity

liquid to resist pouring because of IMF attraction to bulk solution

surface tension

surface phenomenon which an inward force reduces the surface area of liquid

capillary action

surface phenomenon where liquid climbs the walls of the container due to IMF

ΔHvap

energy in IMF must be overcome for liquid on surface to vaporize

properties of liquids inverse to IMF

evaporation rate, vapor pressure, ideality

vapor pressure

pressure of vapor along surface of a liquid

evaporation rate

how quickly a liquid vaporizes from the surface of a liquid

types of solids

molecular, ionic, covalent network, metallic

molecular solids

small, covalent compounds held by IMFs (low MP)

ionic solids

ionic metal cation and nonmetal anion (salt)

metallic solids

between metals

covalent network solids

right side; long chains (diamond, cellulose, graphite, quartz (SiO2)) of covalently bonded atoms (high MP)