Basics of Hydrocarbon Chemistry. Crude oil is a mixture of hydrocarbon molecules, which are organic compounds of carbon and hydrogen atoms that may include from one to 60 carbon atoms. The properties of hydrocarbons depend on the number and arrangement of the carbon and hydrogen atoms in the molecules.
Why does my download stop before it is finished? When a user experiences an issue while downloading files, it is usually a problem with the connection to their Internet service.
Disconnect your computer from the Internet. Errors communicating with the iTunes Store and other Apple services can sometimes cause issues with iTunes startup. If you remove the ability to connect to those services, you can see if those features have issues that need to be resolved.