chemistry topic 7

Question 1

what is crude oil

Answer 1

Crude oil is a finite resource, mixture of hydrocarbons (made up of carbon and hydrogen only)

Question 2

what is the order of the fractions in a fractional distillation column from lowest boiling point to highest boiling point

Answer 2

1. butane and propane
   2 . petrol
2. kerosene
3. Diesel
4. fuel oil

Question 3

describe Fractional distillation

Answer 3

Fractionating column is cool at the top and hot
at the bottom

• Heat crude oil (vaporise it)
• Hydrocarbons evaporate and rise
• When a fraction of the hydrocarbons cool to
  their boiling point they condense
• Liquids are then extracted

Question 4

what effect does Decreasing molecular size have

Answer 4

• boiling point decrease
• viscosity decrease
• flammability increases.

Question 5

Fractions from crude oil can be processed to produce feedstock for the petrochemical
industry. what are useful materials produced from this feedstock?

Answer 5

• Solvents – nail varnish remover
• Lubricants – oil for car engines
• Polymers – polythene and polyvinyl chloride PVC

*Detergents – washing up liquid

Question 6

what does the combustion of hydrocarbons release

Answer 6

energy

Question 7

describe complete combustion

Answer 7

Hydrocarbons are oxidised and produce carbon dioxide and water.

Question 8

what is the prefix is something has one carbon

Answer 8

meth-

Question 9

what is the prefix if something has two carbon

Answer 9

eth-

Question 10

what is the prefix if something has three carbons

Answer 10

prop-

Question 11

what is the prefix if something has four carbons

Answer 11

but-

Question 12

what is the suffix and functional group of Alkanes

Answer 12

-ane

-C-C-

Question 13

what is the suffix and functional group of Alkenes

Answer 13

-ene

-C=C-

Question 14

what is the suffix and functional group of Alcohols

Answer 14

-ol

-COH

Question 15

what is the suffix and functional group of Carboxylic acids

Answer 15

-oic acid

-COOH

Question 16

what is the suffix and functional group of esters

Answer 16

Alkyl- -oate

-COOC-

Question 17

what is the suffix and functional group of Amine

Answer 17

-ine

-NH2

Question 18

what is the general formula for Alkanes

Answer 18

CnH2n+2.

They are ALL SATURATED – no double bonds

Question 19

what is the general formula for Alkenes

Answer 19

CnH2n

UNSATURATED hydrocarbons with a double carbon-carbon
bond.

Question 20

why is there no chemical called methene,

Answer 20

There is no chemical called methene, as the double bond must be between two carbons. Any hydrocarbon starting with meth- can only have one carbon.

Question 21

how do alkenes react in combustion reactions

Answer 21

Alkenes react with oxygen in combustion reactions in the same wayas other
hydrocarbons, but they tend to burn in air with smoky flames because of
incomplete combustion.

Question 22

what is cracking

Answer 22

Hydrocarbons can be broken down (cracked) to produce
smaller more useful molecules.

Question 23

describe Catalytic cracking

Answer 23

the hydrocarbon is heated to a high temperature and a
Zeolite catalyst is used

Question 24

describe Steam cracking

Answer 24

the hydrocarbon is heated and mixed with steam

Question 25

how to test for alkenes

Answer 25

react with orange-brown bromine water to turn it colourless.

Question 26

what can alkenes be used for

Answer 26

Alkenes are used to produce polymers and as starting materials for the production of many other chemicals.

Question 27

What are alkanes?

Answer 27

alkanes are hydrocarbons or are compounds of hydrogen and carbon only

Question 28

what happens when When ethanol reacts with sodium

Answer 28

bubbles of hydrogen gas are given off and colourless sodium ethoxide solution is left

Question 29

what happens when alcohols react with an oxidising reagent

Answer 29

Alcohols can react with an oxidising reagent to make the carboxylic acid e.g. ethanol will oxidise to make ethanoic acid.

Question 30

what are the two process for producing ethanol

Answer 30

* Fermentation – sugar + water + yeast. 25 0C – 45 0C. Anaerobic Glucose → Ethanol + Carbon Dioxide * Hydration – Ethene + steam. 300 0C. Catalyst ethene + Steam → Ethanol

Question 31

what are the important reactions for Carboxylic acids

Answer 31

Carboxylic acid + metal carbonate → salt + carbondioxide + water propanoic acid + Sodium carbonate→ sodium propanoate +carbon dioxide +water Carboxylic acid + alcohol → ester + water Ethanoic acid + ethanol → ethyl ethanoate +water

Question 32

whats the diffrence between strong and week acids

Answer 32

week acids are partially ionised in water strong acids are fully ionised in water

Question 33

how do Alkenes make polymers

Answer 33

addition polymerisation: poly(ethene) and poly(propene)

Question 34

how can esters be made from carboxylic acid

Answer 34

alcohol + carboxylic acid → ester + water

Question 35

what does Condensation polymerisation involve

Answer 35

involves Monomers joining and losing water

Question 36

give examples of natural polymers

Answer 36

DNA – nucleotides Starch – glucose Proteins – amino acids

Question 37

what functional groups do amino acids have

Answer 37

Amino acids have amine – NH2 and carboxylic acid - COOH

Question 38

how can proteins be produced

Answer 38

Different amino acids can be combined in the same chain to produce proteins.

Question 39

DNA molecules are how many polymer chains

Answer 39

two

Question 40

Each nucleotide in DNA contains what

Answer 40

Each nucleotide contains a base, a phosphate and a sugar.