A dark smelly liquid that is a mixture of many different chemical compounds
1 of 28
What are nearly all the compounds in crude oil?
Hydrocarbons
2 of 28
What are hydrocarbons?
Compounds containing only hydrogen and carbon
3 of 28
What are most of the hydrocarbons in crude oil?
Alkanes
4 of 28
What are the first five alkane molecules?
methane, ethane, propane, butane, pentane
5 of 28
What is the general formula of alkanes?
CnH(2n+2)
6 of 28
What type of hydrocarbons are alkanes?
Saturated hydrocarbons
7 of 28
What does a saturated hydrocarbon mean?
They contain as many hydrogen atoms as possible in each molecule
8 of 28
Why is crude oil straight from the ground not much use?
There are too many substances in it, all with different boiling points
9 of 28
What do we have to do before using crude oil?
Separate it into different substances with similar boiling points known as fractions
10 of 28
How can we separate mixtures of substances in crude oil?
By distillation which separates liquids with different boiling points
11 of 28
How can we separate crude oil into fractions?
By fractional distillation
12 of 28
What happens in fractional distillation?
Crude oil is heated and entered into the fractionating column as hot vapour. The temperature decreases going up the column and the gases condense when they reach the temperature of their boiling point. The different fractions are collected as liquids
13 of 28
What are the properties of small hydrocarbon molecules?
They have short-chains, low boiling point, usually a gas, low viscosity, very flammable, burns with a clean flame
14 of 28
What are the properties of large hydrocarbon molecules?
They have long-chains and may have branches, high boiling point, usually a liquid or solid, high viscosity, burns with a smoky flame
15 of 28
What are the most useful hydrocarbons are why?
Short-chain hydrocarbons because they make the best fuel
16 of 28
What is the word equation for the combustion of propane?
propane + oxygen --> carbon dioxide + water
17 of 28
What is the symbol equation of the combustion of propane?
C3H8 + 5O2 --> 3CO2 + 4H2O
18 of 28
What are the products of complete combustion?
Carbon dioxide and water
19 of 28
What does sulfur dioxide and nitrogen oxides cause?
Acid rain
20 of 28
What does carbon dioxide cause?
Climate change
21 of 28
How is carbon monoxide formed?
By incomplete combustion
22 of 28
What is carbon monoxide?
A toxic gas which gives you poisoning
23 of 28
What do particulates cause?
Global dimming and may damage cells in our lungs and even cause cancer
24 of 28
What are biofuels?
Fuels that are made from plants or animal products
25 of 28
How can ethanol be made?
Fermenting sugar solution, extracted from sugar beet or sugar cane, using yeast
26 of 28
What is the word equation for the distillation of ethanol
glucose --> ethanol + carbon dioxide
27 of 28
Why could hydrogen be a fuel in the future?
As it burns well with a very clean flame and there is no carbon in the fuel and it can easily be obtained from water by electrolysis
Comments
No comments have yet been made