Chrmistry Paper 2

Question 1

What is cracking?

Answer 1

Cracking is taking longer chain hydrocarbons molecules and breaking them down into smaller more useful molecules.

Question 2

What is the general formula for alkenes?

Answer 2

CnH2n

Question 3

What is the general formula for alkanes?

Answer 3

CnH2n+2

Question 4

What are the first 5 alkanes?

Answer 4

Methane, ethane, propane, butane and pentane.

Question 5

What is crude oil?

Answer 5

Crude oil is a mixture.

Question 6

How is crude oil formed?

Answer 6

Formed over millions and millions of years from the remains of Dead Sea creatures.

Question 7

What is a finite resource?

Answer 7

A resource in limited quantities.

Question 8

How can you identify an impure substance?

Answer 8

An impure substance has a lower melting point and melts over a temperature change.

Question 9

What is the common trend in impure substances?

Answer 9

Impurities tend to lower the melting point and increase the boiling point.

Question 10

What is a pure substance?

Answer 10

A single element or compound not mixed with any other substances.

Question 11

What are the requirements for cracking?

Answer 11

Cracking requires high temperatures and a catalyst.

Question 12

What is membrane distillation?

Answer 12

Salt water is forced through the membrane sheets at high pressure. Membrane sheets are designed to catch salt ions/ bigger molecules. Water can pass through the membrane but sodium and chlorine can’t.

Question 13

What is desalination?

Answer 13

A process that removes minerals from saline water.

Question 14

What is distillation?

Answer 14

The process if separation of a mixture through selective evaporation. But it requires a lot of energy and is expensive.

Question 15

What is drinking water?

Answer 15

Also known as potable water is water that is safe to drink or to use in food preparation without risk of acute or chronic health impacts.

Question 16

What is pure water?

Answer 16

Also known as purified water is water from a source that has removed all impurities and is fit to drink. Distilled water is the most common form of pure water.

Question 17

What is the simple rule for bonding?

Answer 17

Non metal + non metal = Covalent
Metal + non metal = Ionic
Metal + metal = Metallic

Question 18

What way will the equilibrium shift if the temperature is increased.

Answer 18

The equilibrium will shift in favour of the reaction.

Question 19

What way will the equilibrium shift if pressure is increased?

Answer 19

If pressure is increased the equilibrium will shift in favour of the reaction. So whatever side has less gas molecules is favoured. If the pressure is the same on both sides there’ll be no reaction.

Question 20

What happens if there isn’t enough air for incomplete combustion?

Answer 20

Then incomplete combustion occurs forming carbon monoxide.

Question 21

Why is carbon monoxide poisonous?

Answer 21

Carbon monoxide is toxic because it combines with haemoglobin in the blood to reduce capacity of the red blood cells carrying oxygen.