Q1. The result of a process used to detect and identify the colours in two foods, A and B, is shown. (i) Describe the differences between the colours used in food A and food B. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... (2) (ii) Tick ( ) the name of the process used to detect and identify colours in food. (1) (Total 3 marks) Process ( ) chromatography extraction hardening Page 1 of 22
Transcript
Q1. The result of a process used to detect and identify the colours in two foods, A and B, is shown.
(i) Describe the differences between the colours used in food A and food B.
Q3. Some farmed salmon have a coloured additive in the food that they are given. This is a permitted additive that improves the colour of the fish meat.
A sample of the colour is extracted from a salmon.
Explain how paper chromatography could be used to confirm that this is the permitted additive.
(ii) The base used is copper oxide. Name and give the chemical formula of the acid used.
Name ................................................................................................................
Chemical formula ............................................................................................. (2)
(c) The student wrote about how the copper sulphate was made.
“Some of the acid was warmed. Copper oxide was added. The mixture was stirred. More copper oxide was added until no more would react. The mixture was then filtered.”
Q9. A student tried to make some magnesium sulphate. Excess magnesium was added to dilute sulphuric acid. During this reaction fizzing was observed due to the production of a gas.
(i) Complete and balance the chemical equation for this reaction.
Q10. Limestone is a useful mineral. Every day, large amounts of limestone are heated in limekilns to produce lime. Lime is used in the manufacture of iron, cement and glass and for neutralising acidic soils.
CaCO3 CaO + CO
2
(i) The decomposition of limestone is a reversible reaction. Explain what this means.
Mass of lime = ........................................ tonnes (3)
(Total 5 marks)
Q11. Titanium is a transition metal used as pins and plates to support badly broken bones. Titanium is extracted from an ore that contains the mineral titanium oxide. This oxide is converted into titanium chloride. Titanium chloride is heated with sodium to form titanium metal. This reaction takes place in an atmosphere of a noble gas, such as argon.
4Na(s) + TiCl4(l) → Ti(s) + 4NaCl(s)
Calculate the mass of titanium that can be extracted from 570 kg of titanium chloride.
Q14. Nitrates, such as ammonium nitrate, are added to soil to help plant growth.
(a) When rain falls nitrates dissolve and can end up in drinking water. Nitrates in drinking water can stop respiration in babies. This only happens if there is a lot of nitrate in the drinking water.
Plants use nitrates for growth. Humans need plants. Should large amounts of nitrates be added to soil? Give two reasons for your answer.
(*) if first two bullets not stated accept A has more colours (than B) or B has less colours (than A) for 1 mark only
• A / B have two colours the same
• B has one different colour 2
(ii) chromatography 1
[3]
M2. drinks / colours B and C are safe 1
drinks / colours A and D are not safe
accept a pair of one safe colour and one not safe colour identified for 1 mark accept A, B, C and D all contain one safe colour for 1 mark ignore references to shading
1 [2]
M3. use of solvent / solution / water / any named solvent 1
separates / carries colour(s) / dye(s) allow any idea of movement eg runs / moves
1
match against Rf value / known chromatogram / similar pattern or comparison to permitted additive / colour
removal of coloured additive from salmon does not gain any marks ignore reasons for separation maximum 2 if technique clearly doesn’t work
1 [3]
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M4. any three from:
accept colour 3 is a mixture of colours 1 and 2 for 3 marks
• colour 1 is made up of only one colour / dye
• colour 2 is made up of only one colour / dye
• colour 3 is made up of two colours / dyes
or
more colours (than colours 1 and 2)
• colours 1, 2 and 3 are all different
• colour 1 is less dark than colour 2 accept E-number or additive instead of colour ignore comments about height_ / level
[3]
M5. (i) potassium hydroxide
accept correct formulae 1
water 1
(ii) fertiliser 1
(iii) H+
accept hydrogen but not H 1
[4]
M6. nitric acid 1
potassium hydroxide 1
water 1
[3]
Page 15 of 22
M7. (a) A ammonia
accept correctly indicated in the box 1
B nitrogen monoxide 1
C nitrogen dioxide 1
(b) any two from:
• air / oxygen / O
• ammonia / NH
• water / H O
• nitrogen / N2
(c) (i) speeds up reaction (owtte) 1
(ii) platinum accept indication, circles etc
1 [7]
M8. (a) (i)
accept CaO3 → CaO + CO
2
1
calcium carbonate
→ calcium oxide
+ carbon dioxide
(ii) (thermal) decomposition accept endothermic accept reversible
1
(b) (i) neutralisation accept exothermic
1
(ii) sulphuric (acid) H2SO
4
2
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(c) (i) to speed up the reaction accept to increase the rate of reaction or to increase the number or rate of collisions do not accept “dissolves” copper oxide faster
1
(ii) all acid reacts accept there will be no acid left or acid used up
1
acid is neutralised (for 2 marks)
do not accept to form a concentrated or saturated solution 1
(excess) copper oxide collects in filter paper accept larger particles (of copper oxide) cannot pass through filter paper
1
copper sulphate solution passes through the filter paper accept dissolved copper sulphate passes through filter paper or smaller particles (of copper sulphate) in solution (liquid) pass through filter paper accept (black) solid collects in filter paper and filtrate or soluble solid or (blue) solution (liquid) passes through filter paper for 1 mark only
1 [10]
M9. (i) Mg + (H2SO
4) →
1
MgSO4 + 1
H2
deduct 1 mark if not balanced only if all three correct accept alternative metal of similar reactivity for example Zn or Fe candidate would not then be awarded first mark for Mg then error carried forward deduct 1 mark if not balanced only if all three correct
1
(ii) to remove the (excess) magnesium accept separate accept insoluble substances or solids or residue do not accept unreactive substances or impurities or remove magnesium from sulphuric acid
1
Page 17 of 22
(iii) to evaporate (some of the water or solution) 1
to form crystals or crystallise
accept to form a saturated solution or concentrated solution do not accept to leave MgSO
4
1 [6]
M10. (i) a reaction in which the products can be changed back to reactants
accept a reaction that can go forwards or backwards 1
under certain conditions 1
(ii) Mr CaCO
3 = 100
1
Mr CaO = 56
1
mass of CaO = 140 (tonnes) 1
mark consequentially [5]
M11. 144
accept TiCl4 = 190 for 1 mark accept another correct step in calculation eg 570/190 = 3 for 1 mark
[3]
M12. (a) gives out
heat each for 1 mark
2
(b) chromium and aluminium oxide 1
Page 18 of 22
(c) (i) chromium oxide 1
(ii) oxygen removed/gains electrons 1
[5]
M13. (i) neutralisation/acid base reaction
for 1 mark 1
(ii) 17 (tonnes) give 80 (tonnes) (even if only in working)
for 1 mark each
320 (tonnes) or alternative method) 3 marks for correct answer
(if 17 and 80 not given allow 1 mark for correct answer using their figures) 3
[4]
M14. (a)
the answer yes or no does not gain a mark
Yes – plants will grow faster do not accept grow better
1
more food available, greater yield 1
OR
No – plants still grow without adding nitrates accept the idea that small amounts of nitrate could be used
1
(nitrates) can ‘kill’ babies / causes brain damage do not accept can stop respiration in babies
1
(b) (i) 2 accept two
1
Page 19 of 22
(ii) 2 × 14 + 4 × 1 + 3 × 16 1
= 80 1
% 1
allow 1 mark for correct working for percentage 28/Y × 100, where Y is an incorrect formula mass allow 2 marks for formula mass of 80 where no working or correct working is shown allow 3 marks for 35 where no working or correct working is shown
[6]
M15. (a) This part was not marked 1
(b) electrolysis 1
because calcium is more reactive (than aluminium or carbon)
accept it is more reactive or very reactive
1
OR
in a blast furnace 1
because calcium is less reactive (than carbon or lower) 1
(c) any equation from 1 mark for correct formulae 1 mark for balancing
2ZnO + C → 2Zn + CO2
ZnO + CO → Zn + CO2
ZnO + C → Zn + CO 1
[5]
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M16. (a) (i) 8
ammonia do not credit ammonium
sulphuric acid do not credit just sulphuric; credit sulfuric acid do not credit hydrogen sulphate
3
(ii) (as a) fertiliser 1
(iii) nitric (acid) accept HNO
3 if correct in every detail
1
(b) (i) chemical change (in which) or under suitable conditions
1
product(s) can be converted to reactant(s) or direction of reaction can be reversed or equilibrium can be achieved do not credit reaction can be reversed
1
(ii) air or (the) atmosphere
1
(iii) made of atoms 1
which are all the same credit the idea that the particles (in an element) are all the same even if the name of the particles (the first mark) is incorrect or which have the same number of protons or which have the same atomic number / proton number it cannot be broken down into anything simpler (2) marks
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