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GCSE CHEMISTRY HIGHER AQA PAPER 1 MAY 2018 - Unofficial mark scheme

For many people, here is the answers for the may 2018 aqa paper

1.1 Give one other type of substance that can react with an acid to form a soluble salt.
answer: metal (carbonate)

1.2 Give the formula of calcium nitrate.
answer: Ca(NO3)2

1.3 Describe a method to make pure, dry crystals of magnesium sulfate from a metal oxide and a dilute acid.
answer: use magnesium oxide and sulfuric acid add sulfuric acid to a beaker warm sulfuric acid add magnesium oxide stir continue adding until magnesium oxide is in excess

filter using a filter paper and funnel to remove excess magnesium oxide

heat solution in an evaporating basin to crystallisation point leave to crystallise pat dry with filter paper

2.1 Determine the formula of iron pyrites.

2.2 Give the number of protons, neutrons and electrons in this atom of iron.
2.3 Give two differences between the properties of iron and sodium
answer: iron has a high(er) melting / boiling point iron is dense(r) iron is hard(er)
iron is strong(er) iron is less reactive
iron has ions with different charges iron forms coloured compounds iron can be a catalyst
2.4 Explain why carbon can be used to extract nickel from nickel oxide
answer: carbon is more reactive (than nickel)
(so) carbon will displace / replace nickel (from nickel oxide) or (so) carbon will remove oxygen (from nickel oxide)

2.5 Calculate the percentage atom economy for the reaction to produce nickel.
Relative atomic masses (Ar): C = 12 Ni = 59
Relative formula mass (Mr): NiO = 75

Give your answer to 3 significant figures.

answer: 67.8

Which of these combinations would not give a zero reading on the voltmeter in Figure 2?
answer: C

Why do alkaline batteries eventually stop working?
answer: reactant used up
3.3 Why can alkaline batteries not be rechargeable answer: it is irreversible 3.4
Complete the balanced equation for the overall reaction in a hydrogen fuel cell. answer:
2H2 + O2 2H2O
(edited 5 years ago)
Reply 1
Original post by natgamer

Reply 3
Original post by Molly Dolding


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