Quiz 2 Flashcards
Alkanes
- Flammable! Undergoes combustion reactions
- Nonpolar
- Melting and boiling points are directly proportional to the strength of intermolecular forces
- Strength of London dispersion forces between molecules are directly proportional to the surface area of the molecules
Flammable! Undergoes combustion reactions
alkane + O2 (excess) = CO2 (g) + H2O (g) + energy
alkane + O2 (difficient) = C (s) + 2 H2O (g)
CO (g) + 2 H2O (g)
Nonpolar
- Immiscible (i.e. do mix) with water or other polar molecules
- Very weak London dispersioin forces keep molecules attracted to one another
Strength of London dispersion forces between molecules are directly proportional to the surface area of the molecules
- Boiling points increase substantially with molecular weight
- Boiling points decrease somewhat with braching; i
propane
C3H8, -42 C
butane
C4H10, 0 C
2,2-dimethylpropane
C5H12, 10 C
2-methylbutane
C5H12, 28 C
pentane
C5H12, 36 C
hexane
C6H14, 68 C
1 – 4
gas, heating fuels (natural gas)
5 – 8
volatile, gasoline, non-polar solvents
-liquid evaporates quickly at high vapor pressure
9 – 17
“stable”, kerosene, diesel, jet fuel
18+
“stable”, lubricating oil, asphalt
ALKENES
contains a C = C (unsaturated)
vs. alkanes: more reactive, slightly lower BP/MP