Descriptive chemistry includes predicting products and periodic trends, which were covered in previous tutorials.
Colored compounds
There are several common colored compounds—both soluble and insoluble
Colored soluble compounds |
Colored insoluble compounds |
Soluble copper salts are blue/green |
AgCl is white |
Fe salts are red/brown |
Chromate precipitates are orange |
Cobalt salts are blue |
Dichromate precipitates are yellow |
Complex ions are often colored |
Hydroxide precipitates are white |
Transition metals are often colored.
Many oxides produce colored compounds
Oxide |
Color |
Titanium oxide |
White |
Copper oxide |
Green (patina) |
Iron oxide |
Red (rust) |
Silve oxide |
Black (tarnish) |
Organic chemistry
Organic chemistry is the study of carbon-containing molecules. Simple organic compounds can be found on the AP Exam. Compounds that contain only hydrogen and carbon are hydrocarbons, but many organic molecules contain functional groups. The most common, simple functional groups:
Haloalkane: Halogen replacing a hydrogen on the hydrocarbon; Alcohol: “-OH” replacing a hydrogen on the hydrocarbon; Carboxylic acid: “-COOH” replacing a hydrogen on a hydrocarbon
Properties of organic chemistry
Most are insoluble in water, except: The smallest hydrocarbons and molecules that are polar or have the ability to hydrogen-bond (especially the smaller ones). When they do dissolve in water, they do not dissociate except for carboxylic acids, which are weak acids.
Hydrocarbons: Low melting/boiling points, London Dispersion Forces only, insoluble in water
Haloalkanes: Polar molecules, can exhibit dipole IMF, have higher melting/boiling points than hydrocarbons and are more soluble in water.
Alcohols: polar molecules, can exhibit dipole & hydrogen bonding IMF, have higher melting/boiling points than hydrocarbons and are more soluble
Carboxylic acids: polar molecules, can exhibit dipole & hydrogen bonding IMF’s, having higher melting/boiling points and are more soluble. Are weak acids—dissociate weakly.
Naming simple organic compounds
Carbons are counted in the longest chain, starting from the carbon closest to the functional group.
Prefixes are used to denote number of carbons
Number |
Prefix |
1 |
Meth- |
2 |
Eth- |
3 |
Prop- |
4 |
But- |
5 |
Pent- |
6 |
Hex- |
7 |
Hept- |
8 |
Oct- |
9 |
Non- |
10 |
Dec- |
Suffixes are used for functional groups:
Type |
Suffix |
Alkane |
-ane |
Alkene |
-ene |
Alkyne |
-yne |
Alcohol |
-ol |
Carboxylic acid |
-ic acid |