chem hydrocarbons

What is a hydrocarbon?

a compound made of hydrogen and carbon atoms only

what is simple distillation

evaporation followed by condensation

What is fractional distillation?

A process used to separate mixtures of substances with different boiling points

Steps of fractional distillation of crude oil

-The crude oil is heated up in the fractioning column

• the different hydrocarbons are separated by boiling points hottest at the bottom,, coldest at the top
  -evaporation followed by condensation
  - smaller hydrocarbons collected at the top
  - larger hydrocarbons collected at the bottom

General formula for alkanes

CnH2n+2

general formula for alkenes

CnH2n

Explain the trend in boiling points of the alkanes

as num of atoms increases so does BP . -more intermolecular forces which requie more enrgy to be broken -larger molecules means larger surface area

What is viscosity?

the resistance of a liquid to flow

How is crude oil formed?

It is a fossil fuel formed over millions of years when plankton and other sea creatures die, fall to the sea bed and become covered by layers of sand and silt. Sand and silt means that no oxygen gets to the dead bodies. The heat and pressure builds up and slowly turns them to hydrocarbons which is what crude oil is made up of

Are alkenes more or less reactive than alkanes? Why?

more reactive because unlike alkanes they are unsaturated

what is the test for alkenes and alkanes ?

bromine water changes from orange to colourless if alkene is present but stays orange for alkanes

What is catalytic cracking?

Crack long chain hydrocarbons into smaller more desirable molecules using a catalyst

what is complete combustion

When a fuel burns completely due to enough oxygen being present, and carbon dioxide and water are the products.

What is incomplete combustion?

When a fuel burns in insufficient oxygen

Why is carbon monoxide dangerous?

It is colorless ,odorless, and tasteless and can be fatal

How to test for water

Blue cobalt chloride paper turns pink

how to test for carbon dioxide

Limewater turns milky

What is volatility?

The tendency to turn into a gas

What is flammability?

the ability of a substance to burn

catalytic cracking process

-long chain hydrocarbons heated over a catalyst -broken down into smaller more desireable hydrocarbons

Why are alkanes unreactive?

they are saturated