C9

Question 1

What is a hydrocarbon

Answer 1

Any compound which only contains carbon and hydrogen atoms

Question 2

What is the simplest hydrocarbon

Answer 2

Alkanes

Question 3

What are alkanes

Answer 3

Homolous series (a group of organic compounds which react in a similar way)
Also saturated compounds

Question 4

First 4 alkanes

Answer 4

Methane ethane propane butane

Question 5

When does complete combustion occur

Answer 5

When there is plenty of oxygen

Question 6

Equation for complete combustion questions

Answer 6

Hydrocarbon + oxygen —> carbon dioxide + warer

Question 7

Write a balance equation for the complete combustion of water

Answer 7

CH4 + 2O2 —> CO2 + 2H2O

Question 8

What is a crude oil and how is it formed

Answer 8

Fossil fuel. It is formed from the remains of plants and animals that died millions of years ago and were buried in mud. Over millions of years, high temperatures and pressure, the remains turned into crude oil

Question 9

What is crude oil a mixture of

Answer 9

Hydrocarbons

Question 10

How is crude oil formed

Answer 10

Crude oil is a fossil fuel and is formed from the remains of plants and animals that died millions of years ago and were buried in mud. Over millions of years, with high temp and pressure, the remains turned into crude oils

Question 11

What is fractional distillation?

Answer 11

A method used to seperate different compounds in a crude oil

Question 12

How does fractional distillation work?

Answer 12

The oil is heated until most of it is turned to gas and the gases enter a fractioning column. In the column there is a temperature gradient (hot at the bottom cooler as you go up). They condense back into liquids and drain out of the column early on. You end up with crude oil mixtures seperated out into different fractins

Question 13

What does cracking mean in chemistry

Answer 13

Splitting up long chains of hydrocarbosn

Question 14

What type of reaction is cracking

Answer 14

Thermal decomposition reaction

Question 15

What is a thermal decomoposition reaction

Answer 15

Breaking molecules down by heating them

Question 16

Properties of shorter chain hydrocarbons:

Answer 16

• more runny (less viscous)
• more volatile
• more flammable
  -lower boiling points
• used as bottled gases

Question 17

What are the uses of crude oil?

Answer 17

-fuel for most modern transport
-feedstock to make compounds (polymers, solvents, lubricants)

Question 18

How does bromine water test for alkenes?

Answer 18

The bromine reacts with the alkene to make a coliurless compound - bromine water is decolourised

Question 19

Method of cracking:

Answer 19

1- heat long chain hydrocarbons to vaporise them
2- the vapour is passed over a hot catalyst
3- the long chain molecules split apart on the surface of the specks on the catalyst

Question 20

Steam cracking?

Answer 20

Vaporise hydrocarbons, mix with steam and heat to very high temperatures