Organic Chemistry

Question 1

Alkanes general formula

Answer 1

CnH2n+2

Question 2

Alkene general formula

Answer 2

CnH2n

Question 3

Alcohols general formula

Answer 3

CnH2n+1OH

Question 4

what is a functional group

Answer 4

an atom or group of atoms that determine the chemical properties of a homologous series

Question 5

what are structural isomers

Answer 5

compounds with the same molecular formula, but different structural formulae, including:
C4H10 as CH3CH2CH2CH3 and CH3CH(CH3)CH3

Question 6

what are hydrocarbons

Answer 6

compounds that contain hydrocarbon and carbon only

Question 7

what is a structural formula

Answer 7

unambiguous description of the way the atoms in a molecule are arranged, including:
CH2=CH2, CH3CH2OH, CH3COOCH3

Question 8

homologous series

Answer 8

a family of similiar compounds with similiar chemical properties due to the prescence of the same functional group

Question 9

what does a saturated compound have?

Answer 9

has molecules in which all carbon-carbon bonds are single bonds, e.g. alkanes

Question 10

What does an unsaturated compound have

Answer 10

Has molecules in which one or more carbon-carbon bonds are not single bonds

Question 11

general characteristics of a homologous series as:

Answer 11

1) having the same functional group
2) having the same general formula
3) differing from one member to the next by a -CH2- unit
4) displaying a trend in physical properties
5) sharing similiar chemical properties

Question 12

Fossil fuels

Answer 12

coal, natural gas and petroleum

Question 13

main constituent of natural gas

Answer 13

Methane

Question 14

what is petroleum

Answer 14

a mixture of hydrocarbons

Question 15

describe the seperation of crude oil into useful fractions by fractional distillation

Answer 15

Evaporation of crude oil at high temperatures
Condensation at different fractions
Collection at fractions

Question 16

Describe how the properties obtained from petroleum change from the bottom to the top of the fractionating column

Answer 16

1) decreasing chain length
2) higher volatility
3) lower boiling points
4) lower viscosity

Question 17

Mnemonic to remember order of the fractional distillation of crude oil from smallest number of carbon to highest.

Answer 17

Red Pandas Nag Kittens Dancing Like Fighting Bats
Refinery gas, Petrol, Naptha, Kerosine, Diesel fuel, lubricating oil, fuel oil, bitumen

Question 18

uses of refinary gas fraction

Answer 18

used in heating and cooking

Question 19

uses of gasoline/petrol fraction

Answer 19

for car fuel

Question 20

uses of kerosene/paraffin fraction

Answer 20

for jet fuel

Question 21

uses of naphtha fraction

Answer 21

a chemical feedstock

Question 22

uses of diesel oil/gas oil fractions

Answer 22

for fuel used in diesel engines

Question 23

uses of fuel oil fraction

Answer 23

for fuel used in ships and home heating systems

Question 24

uses of lubricating oil fraction

Answer 24

for lubricants, waxes and polishes

Question 25

uses of bitumen fraction

Answer 25

making roads

Question 26

describe the bonding in alkanes

Answer 26

single covalent and are saturated hydrocarbons

Question 27

properties of alkanes

Answer 27

generally unreactive, except in terms of combustion and substitution by chlorine

Question 28

what type of reaction is the substitution reaction of alkanes with chlorine

Answer 28

photochemical reaction, with ultraviolet light providing the activation energy

Question 29

what happens in a substitution reaction

Answer 29

one atom or a group of atoms is replaced by another atom or group of atoms

Question 30

describe bonding of alkenes

Answer 30

double carbon-carbon covalent bond and unsaturated hydrocarbon

Question 31

manufacture of alkenes and hydrogen

Answer 31

the cracking of larger alkane molecules using a high temperature and a catalyst

Question 32

reasons for the cracking of larger alkane molecules

Answer 32

-it helps to match the supply of fractions with the demand for them - it produces alkenes, which are useful as feedstock for the petrochemical industry

Question 33

test to distinguish between saturated and unsaturated hydrocarbons

Answer 33

Bromination - adding aqueous bromine Adding bromine to unsaturated hydrocarbons go from an orange red to a colourless solution

Question 34

how many products are formed in an addition reaction?

Answer 34

only one

Question 35

Hydrogenation of alkene (adding hydrogen)

Answer 35

E.g. C2H4 + H2 --> C2H6 From alkene to alkane From double bond to single bond - requires nickel as catalyst - occurs at 150C

Question 36

Bromination of alkenes (adding bromine)

Answer 36

E.g. C2H4 + Br2 --> C2H4Br2 Ethene + bromine --> 1,2, -dibromoethane From orange brown colour to colourless

Question 37

Adding steam to alkenes

Answer 37

Hydration: C2H4 + H2O --> C2H5OH (ethene + steam --> ethanol) Double bond breaks and reacts with steam Conditions: phosphoric acid (H3PO4) as catalyst, 300 - 400C, 60 - 70 atm

Question 38

manufacture of ethanol

Answer 38

1) fermentation of aqueous glucose at 25-35C in the prescence of yeast and in the absence of oxygen 2) catalytic addition of steam to ethene at 300C and 6000kPa/60 atm in the prescence of an acid catalyst

Question 39

complete combustion of ethanol

Answer 39

Forms carbon dioxide and water C2H5OH + 3O2 --> 2CO2 + 3H2O

Question 40

uses of ethanol

Answer 40

- fuel - solvent

Question 41

Advantages and disadvantages of the manufacture of ethanol by fermentation

Answer 41

advantages: simple equipment needed, uses renewable resources, low temperature required disadvantages: batch process is inefficient, very slow ROR, produces dilute solution (further processing needed), carbon dioxide is produced (greenhouse gas)

Question 42

Advantages and disadvantages of manufacture of ethanol by the catalytic addition of steam to ethene

Answer 42

Advantages: continuous process is efficient, fast ROR, produces pure ethanol, no greenhouse gas produced Disadvantages: complex set up required, pollutants are formed from the burning of fossil fuels to maintain high temp, requires high temp and pressures (high cost)

Question 43

Carboxylic acid + metals -->

Answer 43

salt + hydrogen

Question 44

Carboxylic acids + carbonates -->

Answer 44

salt, water, and carbon dioxide gas

Question 45

(neutralisation) carboxylic acid + base -->

Answer 45

salt + water

Question 46

what are the endings of a salt formed by the reaction of carboxylic acids

Answer 46

-anoate e.g. magnesium ethanoate

Question 47

ethanoic acid + magnesium -->

Answer 47

magnesium ethanoate + hydrogen (CH3COO)2Mg + H2

Question 48

(neutralisation) propanic acid + potassium hydroxide -->

Answer 48

potassium propanoate + water (CH3CH2COOK + H2O)

Question 49

Describe the formation of ethanoic acid by the oxidation of ethanol:

Answer 49

* with acidified aqueous potassium manganate(VII) * by bacterial oxidation during vinegar production

Question 50

carboxylic acid + alcohol

Answer 50

ester + water (using acid catalyst: sulfuric acid)

Question 51

uses of ester

Answer 51

Perfume (has fruity smell)

Question 52

how to name ester

Answer 52

alcohol-yl carboxylic -oate e.g. ethyl propanoate

Question 53

polymers

Answer 53

large molecules built by linking 50+ smaller molecules called monomers

Question 54

formation of poly(ethene)

Answer 54

example of addition polymerisation using ethene monomers

Question 55

what are plastics made from

Answer 55

polymers