Crude Oil

Question 1

what is crude oil?

Answer 1

crude oil is mixture of hydrocarbons, compounds of hydrogen (H) and carbon (C)

Question 2

what are the four compounds of hydrogen in crude oil?

Answer 2

• C4H10
• C22H40
• C15H32
• C6H6

Question 3

why does crude oil boil over a very large range of temperatures?

Answer 3

because of the different hydrocarbons in crude oil come in a huge variety of shapes and sizes

Question 4

why do we need to separate the oil into fractions which contain similarly used molecules?

Answer 4

because most of the hydrocarbons are useful, but often for very different purposes

Question 5

what is a fraction of crude oil?

Answer 5

each fraction of crude oil is a mixture of similar hydrocarbons with similar boiling points

Question 6

what happens as the boiling points increase of fractions?

Answer 6

1. the fractions get darker in colour
2. the fractions get more viscous (like treacle)

Question 7

what is the order of BP of the fractions of crude oil?

Answer 7

low:
- refinery gases
- gasoline
- kerosene
- diesel
- fuel oil
- bitumen
high:

Question 8

what is the order of molecular mass of the fractions of crude oil?

Answer 8

low:
- refinery gases
- gasoline
- kerosene
- diesel
- fuel oil
- bitumen
high:

Question 9

what is the order of colour in the fractions of crude oil?

Answer 9

light:
- refinery gases
- gasoline
- kerosene
- diesel
- fuel oil
- bitumen
dark:

Question 10

what is the order of viscosity of the fractions of crude oil?

Answer 10

low:
- refinery gases
- gasoline
- kerosene
- diesel
- fuel oil
- bitumen
high:

Question 11

what is the use of refinery gases?

Answer 11

fuel for home cooking

Question 12

what is the use of gasoline?

Answer 12

fuel for cars

Question 13

what is the use of kerosene?

Answer 13

fuel for aircraft

Question 14

what is the use of diesel?

Answer 14

fuel for trains

Question 15

what is the use of fuel oil?

Answer 15

fuel for ships

Question 16

what is the use of bitumen?

Answer 16

making roads

Question 17

what is fractional distillation?

Answer 17

• each of the fractions is separated from crude oil by fractional distillation
• the fractional distillation of crude oil is done industrially on a large scale
• the fractionating column is hotter at the bottom and colder at the top

Question 18

how does a fractionating column work?

Answer 18

1. heated crude oil vapours enter the column
2. vapours rise until they reach their boiling point, when they condense
3. different vapours condense at different heights due to their different boiling points
4. similar vapours condense together as a fraction

Question 19

what are fractions?

Answer 19

fractions are mixtures containing the hydrocarbons that boil in a particular temperature range
e.g. kerosene contains the hydrocarbons that boil between 250 degrees C and 350 degrees C