Unit 1, Topic 4: Introduction to Organics & Alkanes

Question 1

How can risk be reduced and reactions carried out safely? [3]

Answer 1

• working on a smaller scale
• taking precautions specific to the hazard
• using alternative methods involving less hazardous substances

Question 2

What is a homologous series?

Answer 2

Compounds that have the same general formula, same functional group, and similar chemical properties

Question 3

What is a functional group?

Answer 3

A collection of atoms in the compound that determines the chemical properties of said compound

Question 4

What are saturated hydrocarbons?

Answer 4

Substances containing hydrogen and carbon only which has single bonds only between C-C

Question 5

What are unsaturated hydrocarbons?

Answer 5

Substances containing carbon and hydrogen only which contain C=C double bond

Question 6

Name 5 uses of organic chemistry

Answer 6

Pharmaceuticals, cosmetics, detergents, dyes, agriculture

Question 7

Bond breaking can either be…

Answer 7

homolytic: to produce free radicals
or
heterolytic: to produce ions

Question 8

Define ‘nucleophiles’

Answer 8

electron pair donors, are electron-rich, which means they are attracted to places that are electron poor e.g. positive ions

Question 9

Define ‘electropiles’

Answer 9

electron pair acceptors, are electron-poor, so they are attracted to places that are electron rich e.g. negative ions

Question 10

Define ‘free radicals’

Answer 10

unpaired, very reactive electron

Question 11

What are the three main parts of structural isomerism?

Answer 11

Chain isomers, positional isomers, and functional group isomers

Question 12

Explain the formation and use of certain alkanes from crude oil.

Answer 12

1. Fractional distillation occurs where crude oil is separated into fractions due to their different boiling points
2. Catalytic cracking (500C, zeolite catalyst) occurs next where longer chains of hydrocarbons and broken down into shorter chains
3. They are then reformed (converted into straight, branched, or cycloalkane, in some cases aromatic alkane). This is done to help the fuel burn more smoothly and efficiently in car engines. HAS A PLATINUM CATALYST.
   e.g. pentane –> cyclopentane + H2
   e.g. heptane –> methyl benzene + h2
4. Combustion
5. Free radical substitution (UV light is the essential condition)
   e.g. alkane + halogen –> halogen alkane + hydrogen halide5.1 Initiation: produce free radical via homolytic fission
   5.2 Propagation: free radicals keep reacting to produce
   chain reactions
   5.3 Termination: free radicals react with each other to become neutral

Question 13

Explain why carbon monoxide is harmful

Answer 13

1. Toxic
2. Binds with haemoglobin in red blood cell to limit transport of oxygen across the body

Question 14

Explain why nitrogen oxides and sulfur dioxide can damage the environment

Answer 14

1. React with moisture in the air to form acids
2. Acid rain
3. Damages buildings + kill trees + kill aquatic life

Question 15

State methods to reduce sulfur dioxide and nitrogen oxide emission

Answer 15

1. Flue gas desulfurization
2. Catalytic converter (platinum catalyst)
   CO + NO –> CO2 + N2

Question 16

Define ‘carbon neutral’

Answer 16

when there is no net increase of carbon pollutants in the atmosphere

Question 17

Alkane + O2 (excess) –>

Answer 17

CO2 + H2O

Question 18

Alkane + O2 (limited) –>

Answer 18

CO + H2O