hydrocarbons

What are hydrocarbons?

Molecules containing only carbon and hydrogen

Organic chemistry generally consists of molecules containing what?

Molecules containing primarily oxygen + hydrogen, other common elements are nitrogen, oxygen and halogens

What are some uses of hyydrocarbons?

• Fuels

• Waxes

• Detergents

• Polishes

• Lubricant

• Drug

• Paint solvent
  

What are heavy alkanes left behind after fractionation used for?

Used as bitumen tar to surface roads + pavements

Why do hydrocarbons need to be combusted?

Because they release huge amounts of energy (heat) when they react with oxygen generating electrictiy

What is the formula for combustion of hydrocarbons?

Example of hydrocarbon + oxygen goes to carbon dioxide + water

How can we test for CO2 in the successful combustion of hydrocarbons?

• In order to test for CO2, we must bubble gas through solution of calcium hydroxide (limewater)

• Limewater will turn cloudy due to the carbon dioxide’s presence

How can we test for H2O in the successful combustion of hydrocarbons?

• Liquid collected from combustion can be tested with anhydrous copper sulphate

• If water is present, the copper sulphate solid will turn from white to blue.

When does incomplete combustion occur?

When there is a poor or limited supply of oxygen

Formula for incomplete combustion of hydrocarbons

Hydrocarbon + oxygen goes to carbon monoxide or carbon + water

What is bad about incomplete combustion of hydrocarbons?

• Produces carbon which causes global dimming / respiratory problems , carbon monoxide causes toxic gas

Homologous series

Series of organic compounds with a similar general formula, similar chemical properties but different physical properties as of increase in molecular sizes + mass
I.e alkane, alkene and ester

Saturated?

Compound that contains only one single carbon - carbon bond (used as fuel), alkanes

Unsaturated?

Compound that contains at least one carbon - carbon double bond (used to form polymers + alcohol), alkenes