Unit 2

Question 1

Prefixes

Answer 1

METH -1
ETH-2 
PROP-3 
BUT-4
PENT-5
HEX-6
HEPT-7
OCT-8

Question 2

Alkanes

Answer 2

CnH2n+2

• Methane- CH4
• Ethane - C2H6

ALL ALKANES ARE SATURATED HYDROCARBONS( ALL CARBON TO CARBON BONDS ARE COVALENT)

Question 3

Alkenes

Answer 3

CnH2n

• Ethene- C2H4
• Propene- C3H10

ALL ALKENES ARE UNSATURATED HYDROCARBONS(THERE IS AT LEAST 1 CARBON TO CARBON DOUBLE BOND)

Question 4

Cycloalkanes

Answer 4

CnH2n

• Cyclopropane- C3H6
• Cyclobutane- C4H8

ALL CYCLOALKANES ARE SATURATED HYDROCARBONS

Question 5

Homologous series

Answer 5

• family of compounds which can be represented by a general formula (have similar chemical properties)
• as we increase the carbon chain, the boiling point will also increase

Question 6

Isomers

Answer 6

Isomers are compounds with the same molecular formula, but different structures

Question 7

Addition reactions

Answer 7

When a diatomic molecule adds on across the C=C double bond

h h H H
C =C + Br2--------- H-C- C-H h h Br Br

Question 8

Alcohols

Answer 8

-Hydroxyl group (-O-H-) is the functional group(thing that makes it react like does)

                H H -Ethanol- H-C-C-O-H
                H H

ALKANIOLS are a homologous series of alcohols based on corresponding alkanes
The alkanols are a subset of the set of alcohols

Question 9

Oxidations of alcohols

Answer 9

PRIMARY- Orange—— Green/Blue
Secondary - Orange—– Green/Blue
Tertiary- Orange——- Orange(no change)

Primary and secondary alcohols can be oxidised ( primary alcohols can produce carboxylic acids)

Tertiary alcohols cannot be oxidised

Question 10

Carboxylic acids

Answer 10

• Carboxyl group is the functional group(COOH)
• Ethanoic acid is an example of a carboxylic acid

PHYSICAL PROPERTIES

• unplesant smell
• pH 3-5
• soluble in water
• similar mp/bp

CHEMICAL PROPERTIES 
-will react with alkalis, bases, metal oxides (limescale)
-react with alcohols to make an ester 
    H   H   O
H-C - C =\
    H   H     O

Question 11

Esters

Answer 11

• occur in nature
• give fruits their scent
• made of sequence of carbon and oxygen atoms called an ester linkage
• Nail varnish remover
• pineapple
• bananas

Question 12

Complete combustion

Answer 12

BLUE FLAME

Natural gas+ Oxygen—- Carbon dioxide + water

Question 13

Incomplete combustion

Answer 13

YELLOW FLAME

Natural gas+ Oxygen—- Carbon+ carbon monoxide+ water

Question 14

Exothermic reactions

Answer 14

• release energy, to the surroundings

if heat energy is released, there will be a temperature rise in the surroundings

Question 15

Endothermic reactions

Answer 15

-energy is absorbed

Question 16

Bonds

Answer 16

the bonds in compounds are “stored energy”

• To MAKE bonds, we release, or give out energy
• To BREAK bonds, we must put energy in

Question 17

Enthalpy change

Answer 17

The energy difference between the reactants and products in a reaction is called the enthalpy change (Eh)

Eh=cm ΔT
c= specific heat capacity- 4.18 kJ kg-1 c-1 °
m= mass of water in kg
ΔT= the change in temp in °C