Chapter 23: Crude Oil Flashcards

1
Q

What is crude oil?

A

a mixture of HYDROCARBON molecules of different sizes.

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2
Q

How do the physical properties of crude oil change as the number of carbons in the hydrocarbon molecules increase?

A
  • the intermolecular forces get stronger, so require more energy to break
  • the boiling points increase (they become less volatile)
  • they become more viscous (flow less easily)
  • they become darker in colour
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3
Q

How does the industrial process of fractional distillation separate crude oil into fractions?

A
  • crude oil is heated and the vapours are pumped into the bottom of a fractionating column
  • the fractionating column is hotter at the bottom and gets cooler towards the top
  • the vapours rise, cool and condense at different heights depending on their boiling points
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4
Q

Uses of the fractions of crude oil: Refinery gas

A
  • is a mixture of methane, ethane, propane and butane

- used as LPG for domestic heating + cooking

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5
Q

Uses of the fractions of crude oil: petrol

A

Fuel in cars

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6
Q

Uses of the fractions of crude oil: kerosene

A
  • fuel for jet aircrafts
  • domestic heating oil
  • “paraffin” for small heaters + lamps
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7
Q

Uses of the fractions of crude oil: diesel

A

Fuel for vehicles ( or can be converted to petrol)

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8
Q

Uses of the fractions of crude oil: fuel oil

A
  • fuel for ships or industrial heating
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9
Q

Uses of the fractions of crude oil: bitumen

A

melted + mixed with rocks to make the top surface of roads

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10
Q

What is a fuel?

A
  • a substance that releases heat energy when burned
  • hydrocarbons make good fuels
  • when burnt, they react with oxygen to produce carbon dioxide and water
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11
Q

What can happen in car engines?

A
  • temperature is high enough for nitrogen and oxygen from the air to react and form oxides of nitrogen
  • these react to form nitric acid which also causes acid rain
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12
Q

How can the burning of hydrocarbons lead to acid rain?

A
  • sulphur is an impurity in hydrocarbon (fossil) fuels
  • when the fuel is burnt, sodium dioxide is formed
  • this reacts with water and oxygen in the air to form sulphuric acid which causes acid rain
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13
Q

Why do we use catalytic cracking on crude oil fractions

A

the demand for petrol is greater than the supply from fractional distillation of crude oil, so some of the larger fractions, which there are too many of, are converted into smaller, more useful molecules for cracking. This type of reaction is thermal decomposition.

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14
Q

Word equation for cracking

A

Long- chain alkane -> shorter chain alkane + alkene (used to make polymers/plastics)

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15
Q

What conditions are needed for catalytic cracking of crude oil fractions?

A
  • high temperature (600-700 degrees C)

- using silicon dioxide and aluminium oxide catalysts

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