The Rock Cycle
At this site click on chemistry and then on one of the following;
Structure of the Earth.
Erosion and transportation.
The rock cycle.
This site is short and to the point with straight definitions and text.
Look here for information about weathering of rocks.
At this site click on Earth floor. A fun site with explanations and
Crude Oil, Coal and Natural Gas
Have a look at products from oil
Some good pictures of fractional distillation. Quite a detailed site.
Revision guides can be tried at;