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Flashcards in Organic Chemistry Deck (111)
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1

What is crude oil

A mixture of hydrocarbons with a range of boiling points

2

How is crude oil formed

Crude oil was formed millions of years ago from the remains of dead sea creatures that fell to the seabed.
These remains were covered by mud and bacteria and then decayed slowly in the oxygen-free environment.
The deposits became buried under more sediments, and the underground pressure together with heat slowly converted organic matter into crude oil and natural gas.

3

What is fractional distillation

The use of distillation to separate a mixture of miscible liquids, making use of different boiling points

4

How does fractional distillation work

The fractioning column has a large surface area.
Evaporation followed by condensation of the vapour takes place many times on the surface of the fractioning column.
Only the vapour with the lowest boiling point reaches the top of the column and condenses to be collected as a liquid.
This continues until the fraction with the highest boiling point condenses.

5

What happens in the industrial process of fractional distillation

It occurs in a tall tower which is hottest at the bottom and gradually cools towards the top. The process is continuous.
This process pipes off the different fractions at different points in the same column.

6

Give the order of the fractions that come out of crude oil

Refinery gases
Gasoline
Kerosene
Diesel oil
Fuel oil
Bitumen

7

Source for experiment, approx BP, number of carbons and use as fuel of refinery gases

Butane lighter, around 40 degrees, 1-4 carbons, domestic heating and cooking

8

Source for experiment, number of carbons and use as fuel of gasoline

Light petroleum, 4-12 carbons, petrol for motor vehicles

9

Source for experiment, number of carbons and use as fuel of kerosene

Paraffin, 9-16 carbons, jet aircraft fuel

10

Source for experiment, number of carbons and use as fuel of diesel oil

Petroleum, 15-25 carbons, diesel fuel for cars and lorries

11

Source for experiment, number of carbons and use as fuel of fuel oil

Central heating oil, 20-70 carbons, oil powered central heating systems

12

Source for experiment, approx BP, number of carbons and use as fuel of bitumen

Bitumen paint, around 400 degrees, more than 70 carbons, road making

13

What happens to the BP, volatility and viscosity as the number of carbon atoms in the molecule increases

BP increases
Liquids become less volatile
Liquids become for viscous
Burn less easily

14

Why does BP increase as the number of carbon atoms in the molecule increases

Because there are larger intermolecular attractions between larger molecules so more energy is needed to separate the hydrocarbon molecules.

15

Why do liquids become less volatile as the number of carbon atoms in the molecule increases

Larger molecules evaporate more slowly because there are stronger intermolecular attractions

16

Why do liquids become more viscous as the number of carbon atoms in the molecule increases

Because of greater intermolecular attractions

17

What are the dangers of incomplete combustion

If a hydrocarbon is is burnt in a limited supply of oxygen, carbon monoxide is formed. This is toxic to humans because it reduces the capacity of the blood to carry oxygen.

18

What is photochemical smog and the dangers

In a car engine, the temperature is high enough that nitrogen and oxygen rom the air react to form nitrogen oxides. These react in the air with hydrocarbons to form photochemical smog. This can lead to poor air quality and respiratory diseases

19

What is acid rain and the dangers

If sulphur is present in fuels, sulphur dioxide may form when they are burnt.
This dissolves in water droplets in the atmosphere to form sulphuric acid.
This can cause damage to plants, animals and limestone buildings. Nitrogen oxides dissolve in water to form acid rain too

20

What are hydrocarbons

Molecules made up of hydrogen and carbon atoms only

21

What does organic mean

A compound containing at least one carbon-hydrogen bond

22

What is a homologous series

A family of compounds with similar properties due to their similar bonding. They have the same general formula

23

What does saturated mean

A compound consisting of single bonds ONLY

24

What does unsaturated mean

A compound containing a carbon-carbon double bond

25

What is the definition of "general formula"

A formula that describes a homologous series from which you can derive the molecular formula

26

What is the definition of the "molecular formula"

Formula that describes the number of each type of atom in a molecule

27

What is the definition of the "empirical formula"

The simplest whole number ratio of atoms

28

What are (structural) isomers

Molecules with the same molecular formula but different structural formula

29

What are isotopes

Atoms of an element with a different number of neutrons

30

What is an allotrope

Forms of an element that exist in the same state but have different properties because the atoms are arranged differently