3) less dense than H2O, mainly gasses
4) Insoluble - doesn’t mix with H2O
Gas: 4 carbon atoms
Liquid: 4 – 17 carbon atoms
Solid: 17+ carbon atoms
Hydrocarbons + burning --> Carbon dioxide + water
When there is a lack of oxygen: Hydrocarbons + burning --> Carbon monoxide + soot
Alkanes don’t react with aqueous reagents e.g. acids or alkali’s.
This is because they are saturated – their C – H and C – C bonds are difficult to break = highly un-reactive.
The formula CnH (2n+2), where n = no of carbon atoms, can be used to determine the formula for each alkane. E.g. To find propane: C3H (2x3 +2) = C3H8
Remember state symbols + balancing the equation
The alkenes are unsaturated and are more reactive b/c of the C =C double bond.
The double bond allows them to melt and form into different things e.g. plastic
You got it now!