C1 - carbon chemistry

Question 0

What is crude oil?

Answer 0

Crude oil is a mixture of many types of oil, which are all hydrocarbons. A hydrocarbon is made up of molecules containing carbon and hydrogen only.

Question 1

What are specific difficulties associated with the finite nature of crude oil?

Answer 1

• All the readily extract able resources will be used up in the future.
• Finding replacements.

Question 2

How can crude oil be separated?

Answer 2

Crude oil can be separated because the hydrocarbons in different fractions have differently sized molecules.

• the forces between the molecules are intermolecular forces and are broken during boiling.
• the molecules of the liquid separate from each other, as molecules of gas
• large molecules, such as those of bitumen and heavy oil, have strong forces of attraction. A lot of energy is needed to break the forces between the molecules. These fractions have high boiling points.
• smaller molecules, such as petrol, have weak attractive forces between them and are easily separated. Less energy is needed to break the forces between molecules. These fractions have low boiling points.

Question 3

What’re the problems in transporting oil?

Answer 3

Oil slicks can damage birds’ feathers and cause their deaths. Clean-up operations use detergents that can damage wildlife.

Question 4

What are some potential political problems involved in extracting crude oil?

Answer 4

Oil-producing nations (particularly politically unstable countries) can set high prices and cause problems for the future supply of non-oil producing nations.

Question 5

Why is there conflict between what crude oil needs to be used for?

Answer 5

Because the demand for oil and its products is very high, there is a conflict between the need for making petrochemicals and for making fuels. A fraction called naphtha is in high demand for use in plastics, medicines and dyes.

Question 6

What is cracking?

Answer 6

Cracking is a process that turns large alkane molecules into smaller alkane and alkene molecules. An alkene molecule has a double bond, which makes it useful for making polymers.

Cracking also helps oil manufacturers match supply with demand for products like petrol.

Question 7

What is complete combustion and the equation for it?

Answer 7

Complete combustion occurs when a fuel burns in plenty of oxygen.
-more energy is released during complete combustion than during incomplete combustion.

methane + oxygen = carbon dioxide + water

CH(four) + 2O(two) = CO(two) + 2H(two)O

Question 8

What is incomplete combustion and the equation for it?

Answer 8

Incomplete combustion happens when fuels do not burn in enough oxygen. Carbon monoxide and carbon is made during incomplete combustion.

fuel + oxygen = carbon monoxide + water

OR

fuel + oxygen = carbon + water

2CH(four) + 3O(two) = 2CO + 4H(two)O

OR

CH(four) + O(two) = C + 2H(two)O

Question 9

What is clean air?

Answer 9

Clean air is made up of 78% nitrogen, 21% oxygen and of the remaining 1% only 0.035% is carbon dioxide.

Question 10

Why has the percentage of carbon dioxide in the air increased in the last few centuries?

Answer 10

• deforestation, as more rain forests are cut down, less photosynthesis takes place
• increased population, as populations increase, the worlds energy requirements increase

Question 11

Gases come from the centre of the earth through volcanoes in a process called degassing. What theories have scientists made about the original atmosphere?

Answer 11

One theory is that the atmosphere was originally rich in water vapour and carbon dioxide. This vapour condensed to form oceans and the carbon dioxide dissolved in the water. The percentage of nitrogen increased slowly and, being unreactive, little nitrogen was removed.

Over time, organisms that could photosynthesise evolved and converted carbon dioxide and water into oxygen. As the percentage of oxygen in the atmosphere increased, the percentage of carbon dioxide decreased, until today’s levels were reached.

Question 12

What can the pollutant sulfur dioxide do?

Answer 12

Sulfur dioxide is a pollutant that can cause difficulties for people with asthma. It can also dissolve in water to form acid rain that damages wildlife and limestone buildings.

Question 13

What does a catalytic converter do?

Answer 13

A catalytic converter changes carbon monoxide into carbon dioxide. In a catalytic converter, a reaction between nitric oxide and carbon monoxide takes place on the surface of the catalyst. The two gasses formed are nitrogen and carbon dioxide.

2CO + 2NO = N(two) + 2CO(two)

Question 14

What is a hydrocarbon?

Answer 14

A hydrocarbon is a compound of carbon and hydrogen atoms only.

Question 15

What’s an alkane?

Answer 15

Alkanes are hydrocarbons that have single covalent bonds only.

Question 16

What’s an alkene?

Answer 16

An alkene is a hydrocarbon that has a double covalent bond between carbon atoms.

Question 17

How is bromine used to test for an alkene?

Answer 17

When orange bromine water is added to an alkene it decolourises.

The bromine and alkene form a new compound by an addition reaction. A dibromo compound forms which is colourless.

Question 18

What’s a saturated compound?

Answer 18

A saturated compound has only single covalent bonds between carbon atoms.

Question 19

What is an unsaturated compound?

Answer 19

An unsaturated compound had at least one double covalent bond between carbon atoms.

Question 20

What is polymerisation?

Answer 20

Addition polymerisation is the process in which many alkene monomers react to give a polymer. This reaction needs high-pressure and a catalyst. Addition polymerisation involves the reaction of many unsaturated monomer molecules (alkenes) to form a saturated polymer.

Question 21

What are the properties of nylon?

Answer 21

Nylon is tough lightweight keeps water out and keeps UV light out but does not let water vapour through.This means that swept condenses and makes the wearer wet and cold inside their jacket.

Question 22

How is gore-tex better than nylon?

Answer 22

Gore-Tex Has all the properties of nylon but it is also breathable so it is won by many active outdoor people water vapour from sweat can pas through the membrane but rainwater cannot.

Gore-Tex is made from PTFE. The holes in PTF E are to small for water to pass through that are big enough for water vapour to pass through.

PTFE membrane is too fragile on its own and so it is laminated onto nylon to produce a stronger fabric.

Question 23

What new types of polymers are scientists developing?

Answer 23

Polymers that dissolve and biodegradable polymers.

Question 24

What are the environmental and economic issues with the use of existing polymers?

Answer 24

Disposal of non-biodegradable polymers means landfill sites get filled quickly.
Landfill means wasting land that could be valuable for other purposes.
Disposal by burning waste plastics makes toxic gases.
Disposal by burning or using landfill sites wastes the crude oil used to make the polymers.
It is difficult to sort out different polymers so recycling is difficult.

Question 25

Explain weak intermolecular forces in plastics

Answer 25

Plastics that have a weak intermolecular forces between polymer molecules have low melting points and can be stretched easily as the polymer molecules can slide over each other.

Question 26

Explain strong intermolecular forces in plastics

Answer 26

Plastics that have strong forces between the polymer molecules (cabling bonds or crossed linked bridges) have high melting point cannot be stretched and are rigid.

Question 27

What happens to protein molecules when they are cooked?

Answer 27

They are denatured. The texture of eggs or meat changes when it is cooked because the shape of the protein molecules change permanently.

Question 28

Why is carbohydrate easier to digest if it is cooked?

Answer 28

The starch grains swell up and spread out

The cell walls rupture resulting in the loss of their rigid structure so a softer texture is produced

Question 29

Baking powder is sodium hydrocarbonate. What is the word equation and symbol equation for the decomposition of sodium hydrocarbonate?

Answer 29

Sodium hydrocarbonate goes to sodium carbonate plus carbon dioxide plus water

2NaHCO cubed = Na squared CO cubed + CO squared + H squared O

Question 30

How do emulsifiers keep oil and water from separating?

Answer 30

• The hydrophilic end bonds to the water molecules
• The hydrophobic end bonds with the oil or fat molecules
• The hydrophilic end is attracted to the water molecules which surround the oil, keeping them together

Question 31

What does an alcohol an acid make?

Answer 31

Alcohol + acid = ester + water

Esters are used to make perfumes

Question 32

What properties must a perfume have?

Answer 32

• evaporate easily so that the perfume particles can reach the nose
• be non-toxic
• not react with water so the perfume does not react with perspiration
• not irritate the skin so the perfume can be put directly onto the skin
• be insoluble in water so it cannot be washed off easily

Question 33

What is a solution?

Answer 33

A solution is a mixture of solvent and solute that does not separate out. Esters can be used as solvents.

Question 34

Explain the ease of evaporation of perfumes in terms of kinetic theory

Answer 34

In order to evaporate, particles of a liquid need sufficient kinetic energy to overcome the forces of attraction to other molecules in the liquid

Only weak attractions exist between particles of the liquid perfume so it is easy to overcome these attractions as they have sufficient kinetic energy

Question 35

Why will water not dissolve nail varnish colours?

Answer 35

• the attraction between the water molecules is stronger than the attraction between the water molecules and the nail varnish molecules
• the attraction between the nail varnish molecules is stronger than the attraction between water molecules than the now varnish molecules

Question 36

What is a colloid?

Answer 36

Paint is a colloid where the particles are mixed and dispersed with particles of a liquid but are not dissolved

Question 37

Why does paint dry?

Answer 37

Paints are applied as a thin layer and the solvent evaporates.

Emulsion paints and water based paints that dry when the solvent evaporates

Oil paints dry because the solvent evaporates and the oil is oxidised by atmospheric oxygen