Organic Chemistry

Question 1

Define homologous series

Answer 1

A family of organic compounds where they have a same general formula, similar chemical properties, gradual change in physical properties and Differ by CH2 down the group

Question 2

Which 2 elements make up a hydrocarbon

Answer 2

Hydrogen and carbon

Question 3

What is the general formula of Alkanes

Answer 3

C(n)H(2n+2)

Question 4

What does the prefix meth mean

Answer 4

1

Question 5

What does the prefix eth mean

Answer 5

2 carbons

Question 6

What does the prefix prop mean

Answer 6

3 carbons

Question 7

What dies the prefix but mean

Answer 7

4 carbons

Question 8

Define fossil fuels

Answer 8

Fossil fuels are formed over millions of years from dead plants and animals. Eg crude oil, peat and natural gas

Question 9

What is fractional distillation

Answer 9

Continual process of evaporation and condensation.

Question 10

How does a fractionating column work?

Answer 10

When hydrocarbons enter the column they are vaporised. As they rise up through the column different compounds condense at their different boiling points.

Question 11

What are the 3 stages of the petro-chemical industry

Answer 11

1. Extracting crude oil from its source
2. Transported to refineries, fractional distillation separates it into different hydrocarbons
3. Hydrocarbons obtained by fractional distillation are used not only as fuels but used in the manufacture of dyes, plastics, fertilisers, medicines, paints and lubricants

Question 12

What are environmental concerns of the petrochemical industry

Answer 12

Transports of crude oil can result in spills and leakages
Drilling for oil in the sea bed can result in leaks
Air pollution by burning fossil fuels as carbon dioxide is released

Question 13

Define cracking

Answer 13

Cracking is the breakdown of larger/longer (less useful) saturated hydrocarbon molecules (alkanes) into smaller/shorter more useful ones, some of which are unsaturated (alkenes).

Question 14

Define combustion

Answer 14

The reaction in which a fuel reacts with oxygen producing oxides and releasing heat

Question 15

What is complete combustion

Answer 15

Burning in an excess of air (more than enough), when all the carbon turns into carbon dioxide

Question 16

What is incomplete combustion

Answer 16

Gives carbon monoxide and water

Question 17

What is the word equation for complete combustion

Answer 17

Hydrocarbon + oxygen —> Carbon dioxide + water + (energy)

Question 18

What is the equation for incomplete combustion

Answer 18

Hydrogen + oxygen —> carbon monoxide + water + (energy)

Question 19

What is the use for refinery gases

Answer 19

Bottled gasses

Question 20

What is the use for petrol

Answer 20

Fuel for cars

Question 21

What is the uses of Naptha

Answer 21

Chemicals and plastics

Question 22

What is the use of kerosene

Answer 22

Fuel for aircraft

Question 23

What is the use of diesel

Answer 23

Fuel for cars and trains

Question 24

What is the use of fuel oil

Answer 24

Fuel for ships

Question 25

What are uses of bitumen

Answer 25

Surfacing roads as raid tar and sealing roofs

Question 26

In extreme circumstances with an inadequate supply of oxygen for combustion what can be produced

Answer 26

Soot Hydrocarbon + water —> carbon + water

Question 27

What is the test for carbon dioxide

Answer 27

Bubble through limewater, will turn milky

Question 28

How is carbon monoxide a toxic gas

Answer 28

It combines with haemoglobin in the blood reducing its capacity to carry oxygen. It is colourless and odourless

Question 29

What is the general formula for alkenes

Answer 29

C(n)H(2n)

Question 30

What is an alkene and what makes it different to an alkane

Answer 30

Alkenes are another example of a homologous series, they are also hydrocarbons. They are said to be unsaturated as they have one carbon-carbon double bond

Question 31

What are the first 4 alkenes

Answer 31

Ethene Propene But-1-ene But-2-ene

Question 32

Define alkene

Answer 32

An unsaturated compound which contains at least one c=c double bond

Question 33

Define functional group

Answer 33

Reactive group in a molecule

Question 34

What colour flame does alkenes burn in

Answer 34

Orange

Question 35

What colour flame does an alkane burn in

Answer 35

Blue

Question 36

Why can alkenes easily go under addition reactions

Answer 36

The double bond breaks and atoms add onto the two carbon atoms across the double bond. The product then contains a c-c single bond and is saturated

Question 37

How to distinguish between an alkane and an alkene

Answer 37

Shaking hydrocarbon with bromine water. An addition fraction takes place where bromine molecule adds across the double bond of alkene to produce a halogenalkane. Colour change can be seen in alkene as it goes from orange to colourless.

Question 38

Word equation of addition reaction of ethene with hydrogen

Answer 38

Ethene + hydrogen —> ethane Nickel catalyst also used

Question 39

Word equation of Ethene with steam (addition reaction)

Answer 39

Ethene + steam —> ethanol Phosphoric acid catalyst used and done at high temp