1.
(a)
The formula for ammonia is NH3. What does the formula tell you about each molecule of ammonia?
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(3)
(b) Ammonia is used to make nitric acid (HNO3). Calculate the formula mass (Mr) for nitric acid. (Show
your working).
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(3)
(Total 6 marks)
2.
Calculate the formula mass (Mr), of the compound
calcium hydroxide, Ca (OH)2.
(Show your working)
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(Total 3 marks)
3.
The formula for the chemical compound magnesium sulphate is MgSO4.
Calculate the relative formula mass (Mr) of this compound. (Show your working.)
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(Total 2 marks)
4.
Ammonium chloride, NH4Cl, is made up of nitrogen, hydrogen and chlorine atoms.
(i)
Complete the table to show the number of atoms of each element present in NH4Cl.
Element
Number of atoms in NH4Cl
nitrogen
1
hydrogen
chlorine
(1)
(ii)
Calculate the relative formula mass of ammonium chloride, NH4Cl.
(Relative atomic masses: H = 1, N = 14, Cl = 35.5)
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Relative formula mass = .................................................
(2)
(Total 3 marks)
5.
The symbol equation below shows the reduction of iron (III) oxide by carbon monoxide.
Fe2O3
(a)
+

3CO
2Fe
+
3CO2
Calculate the formula mass of iron (III) oxide.
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(3)
(b) What percentage (%) of iron (III) oxide is iron?
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Answer ........................................ %
(2)
(Total 5 marks)
6.
(a)
Calculate the formula mass (Mr) of the compound iron (III) oxide, Fe2O3.
(Show your working.)
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(3)
(b) Calculate the mass of iron produced when 32g of iron (III) oxide is completely reduced by aluminium.
The reaction is shown in the symbol equation:
Fe2O3
+
2Al

2Fe
+
Al2O3
(Show your working.)
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Answer = ..................................... grams
(3)
(Total 6 marks)
7.
(a)
The formula for the chemical compound magnesium sulphate is MgSO4.
Calculate the relative formula mass (Mr)of this compound. (Show your working.)
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(2)
(b)
Magnesium sulphate can be made from magnesium and dilute sulphuric acid.
This is the equation for the reaction.
Mg
+
H2SO4

MgSO4
+
H2
Calculate the mass of magnesium sulphate that would be obtained from 4g of magnesium.
(Show your working.)
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Answer..................................... g
(2)
(Total 4 marks)
8.
In this question you will need to use the following information:
The diagram shows a chemical reaction taking place in a conical flask.
Dilute hydrochloric acid
Magnesium ribbon
The balanced equation for this reaction is:
Mg(S)
+
2HCl(aq)

MgCl2(aq)
+
H2(g)
Calculate the mass of magnesium required to produce 0.50 g of hydrogen. Show clearly how you work out your
final answer and give the unit.
(Relative atomic masses: H = 1, O = 16, Mg = 24)
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Mass = ............................
(Total 2 marks)
9.
Quicklime can be converted to slaked lime. The equation which represents this reaction is shown below.
CaO(s) + H2O(l)  Ca(OH)2(s)
quickline
slaked line
(i)
Why do farmers sometimes add slaked lime to acidic soil?
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(1)
(ii)
Use these relative atomic masses: H = 1; O = 16; Ca = 40
to calculate the relative formula mass (Mr) of
quicklime CaO ...........................................................................................................
slaked lime Ca(OH)2 ..................................................................................................
(2)
(iii) Calculate the mass of slaked lime that could be made from 1000 kg of quicklime.
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Mass of slaked lime .................... kg
(2)
(Total 5 marks)