Hydrocarbons

Question 1

What is a hydrocarbon? technical

Answer 1

• any compound that’s formed from hydrogen and carbon atoms only so C10H22 (DECANE AN ALKANE) is a hydrocarbon

Question 2

What is an alkane and what’s the general formula for them?

Answer 2

• simplest type of hydrocarbon you can get
  = Cn H2n + 2

Question 3

What is an alkane ? (definition)

Answer 3

• Alkanes are a homologous series - a group of organic compounds that react in a similar way
  They are saturated compounds = each carbon atom forms 4 covalent bonds

Question 4

What are the first 4 alkanes

Answer 4

• Methane CH4, Ethane C2H6 , Propane C3H8 , Butane C4H10

Question 5

As the length of the carbon chain changes, the properties of the hydrocarbon changes.
But how?

Answer 5

The shorter the carbon chain = the more runny a hydrocarbon is = less viscous
The shorter the carbon chain = more volatile = lower bp
The shorter the carbon chain = the more flammable the hydrocarbon is

Question 6

How does the properties of the hydrocarbon affect how they’re used for ..

Answer 6

fuels

• shorter carbon chain =lower bp = used as ‘bottles glass’ - stored under pressure as liquids in bottles

Question 7

When does complete combustion happen and what does it do?

Answer 7

When there’s plenty of oxygen
The complete combustion of any hydrocarbon in oxygen releases alot of energy

Question 8

The waste products of complete combustion

Answer 8

= co2 and water
for example
Hydrocarbon + Oxygen -> c02 and water (+ energy)

Question 9

During combustion, what happens to both carbon and hydrogen from the hydrocarbon

Answer 9

• oxidised

Question 10

What are hydrocarbons used as and why?

Answer 10

Fuels due the amount of energy released when they combust completely

• You need to give a balanced symbol equation for the complete combustion of a simple hydrocarbon -
  Do question 1 and 2 on page 150 of AQA revision guide