topic 4

Question 1

what is the reactions of group 2 metals with oxygen

Answer 1

metal + oxygen -> metal oxide

Question 2

what is the reactions of group 2 metals with chlorine

Answer 2

metal + chlorine -> metal chloride

Question 3

what is the reaction of group 2 metals with water

Answer 3

metal + (cold) water -> metal hydroxide + hydrogen

Question 4

what are the group 1 flame colours

Answer 4

lithium- red
sodium- yellow
potassium- lilac
rubidium- red
caesium- blue

Question 5

what are the group 2 flame colours

Answer 5

magnesium- no flame colour
calcium- orange-red
strontium- red
barium- pale green
copper- blue-green

Question 5

why does magnesium have no flame colour

Answer 5

energy released isnt in visible light spectrum

Question 5

what colour is chlorine at room temperature

Answer 5

pale green gas

Question 5

what colour is bromine at room temp

Answer 5

brown liquid

Question 5

what colour is iodine at room temp

Answer 5

grey-black solid

Question 5

what colour is chlorine in aqueous solution

Answer 5

pale green

Question 5

what colour is bromine is aqueous solution

Answer 5

orange/yellow

Question 5

what colour is iodine in aqueous solution

Answer 5

brown

Question 5

what colour is chlorine when dissolved in a hydrocarbon solvent

Answer 5

pale green

Question 5

what colour is bromine when dissolved in hydrocarbon solvent

Answer 5

red

Question 6

what colour is iodine in hydrocarbonsolvent

Answer 6

purple

Question 7

what is the experimental procedure for thermal decomposition

Answer 7

-measure some of the carbonate into a test tube
- fit a delivery tube to the test tube and clamp it so that the delivery tube end in a second test tube containing limewater
- heat the test tube containing the carbonate and then heat it more strongly

Question 8

how can you test for chlorine

Answer 8

chlorine turns damp blue litmus red and then bleaches it
chlorine also displaces bromine and iodine from bromide or iodide solutions

Question 9

how can you test for bromine

Answer 9

bromine is orang/red when dissolved in an organic solvent
bromine displaces iodine from an iodide solution

Question 10

how can you test for iodine

Answer 10

iodine turns starch black
is also decolourised by thiosulphate solution
its brown in water but purple in organic solvents

Question 11

what kind of solvents do halogens dissolve in

Answer 11

non polar solvents such as hexane

Question 12

why does the colour change occur in halogen displacement reactions

Answer 12

when the halogn is displaced, the solution turns into the colour of the halogen that is displaced in aqueous solution
e.g if iodine is displaced, aqueous solution would turn brown (which is its colour when dissolved in aqueous solution)

Question 13

why does reducing power increase down group 7?

Answer 13

this is because the halide ion becomes larger
outer electrons are further from the nucleus
less attraction between the nucleus and the outer e-
easier to lose e- do it can be used to reduce other species (and donate its electron)

Question 14

when concentrated sulfuric acid is added to (e.g potassium) chloride what can be produce

Answer 14

misty white fumes
hydrogen halide is formed
KHSO4

Question 15

when concentrated sulfuric acid is added to (potassium) bromide what can be produced

Answer 15

brown misty fumes
bromine gas is formed
sulphur dioxide is formed

Question 16

when concentrated sulfuric acid is added to (potassium) iodide what can be produced

Answer 16

iodine gas water sulphur dioxide suphur hydrogen sulphide

Question 17

what are the colours of the precipitates formed when silver nitrate is added to halides

Answer 17

silver halide forms silver chloride- white silver bromide- cream silver iodide- yellow

Question 18

what is the effect of sunlight on the halides

Answer 18

chloride- white precipitate turns purple- grey bromide- cream precipitate turns green- yellow iodide- no effect

Question 19

what happens when ammonia solution is added to halides

Answer 19

chloride- precipitate dissolves in dilute and conc. ammonia solution bromide- precipitate dissolves in conc. ammonia solution iodide- doesnt dissolve

Question 20

what is the disproportionation reaction of chlorine with water

Answer 20

Cl2(g) + H2O(l) -> HClO(aq) + HCL(aq)

Question 21

what is the reaction of chlorine with cold dilute sodium hydroxide

Answer 21

disproportionates to chlorate (I) and chloride 2NaOH + CL2 -> NaCl + NaClO + H2O

Question 22

what is the reaction of chlorine with hot concentrated sodium hydroxide solution

Answer 22

3Cl + 6NaOH -> 5NaCl + NaClO3 + 3H2O

Question 23

how do you test for carbonate ions

Answer 23

add dilute hydrochloric acid is added to the test compound bubbles of gas produced which is carbon dioxide limewater is used to confirm that the gas is CO2

Question 24

how to test for sulphate ions

Answer 24

detected using barium chloride - add a few drops of dilute hydrochloric acid - then add a few drops of barium chloride solution - a white precipitate of barium sulphate forms if sulphate ions are present

Question 25

how can you test for ammonium ions (NH4+)

Answer 25

- add dilute sodium hydroxide and gently warm is ammonium ions present - ammonia gas will form - ammonia gas turns damp red litmus paper blue

Question 26

What is the formula for group 1 carbonates

Answer 26

X2CO3

Question 27

What is the formula for group 2 nitrates

Answer 27

X(NO3)2

Question 28

What is the formula for group 1 nitrates

Answer 28

XNO3

Question 29

What is the formula for group 2 carbonates

Answer 29

XCO3

Question 30

why is iodine unable to displace bromine or chlorine

Answer 30

its a weaker oxidising agent than them both

Question 31

how can you compare the rate of decomposition of carbonates

Answer 31

use of delivery tube to bubble gas into limewater compare time taken for lime water to go cloudy

Question 32

what is the trend in reactivity of haloalkanes

Answer 32

increases down the group this is because the C-X bond enthalpy decreases