 Chemistry Edexcel iGCSE:
Calculations 1b

For Double and Triple sciences

Grab a calculator and a copy of the periodic table

(This test has only 10 questions, but may take 15 - 20 mins).

Q1-3:  A student used the following reaction to try to produce 20.0 g of copper(II)chloride.

CuCO3 + 2HCl  CuCl2  + H2O  + CO2

[Relative atomic masses Cl = 35.5; Cu = 63.5]

1. The formula mass of copper(II)chloride and the number of moles of copper(II)chloride produced is …

 Formula Mass Moles produced A 99 4.95 B 99 0.202 C 134.5 6.73 D 134.5 0.149
2. What mass of copper(II)carbonate does the student need to react with excess hydrochloric acid to make the 20.0 g of copper(II)chloride? [Mr of CuCO3 = 123.5]
• A.   18.4 g
• B.   20.0 g
• C.   24.9 g
• D.   36.8 g
3. If the percentage yield of copper(II)chloride in this reaction was only 72% what mass of copper(II)chloride did the student actually produce?
• A.   7.2 g
• B.   14.4 g
• C.   27.8 g
• D.   1440 g

4. In the thermite reaction aluminium powder reacts very exothermically with iron(III)oxide displacing molten iron. The equation for the reaction is:

2Al + Fe2O3  Al2O3 + 2Fe

What mass of molten iron is formed from 0.1moles of iron(III)oxide?
[Mr of Fe2O3 is 160; Ar of Fe is 56] • A.   2.8 g
• B.   5.6 g
• C.   11.2 g
• D.   22.4 g

Q5-7:
1.23 g of hydrated magnesium sulfate, MgSO4.xH2O, was heated to constant mass in a crucible.
0.60 g of anhydrous magnesium sulfate, MgSO4, remained at the end.
[Relative formula masses: MgSO4 = 120; H2O = 18]

5. Calculate the number of moles of anhydrous magnesium sulfate produced.
• A: 0.0050
• B: 0.010
• C: 0.50
• D: 2.0
6. Calculate the number of moles of water released.
• A: 0.033
• B: 0.035
• C: 0.068
• D: 0.050

7. Determine the value of ‘x’ in the MgSO4.xH2O

8. A mass of 3 g of magnesium was reacted with 0.200 moles of ethanoic acid in the following reaction:

Mg + 2CH3COOH  (CH3COO)2Mg + H2

Calculate the number of moles of magnesium used and determine the reagent in excess.

 Number of moles of magnesium Reagent in excess A 0.125 Ethanoic acid B 0.125 magnesium C 0.1 Ethanoic acid D 0.1 magnesium
9. An ore of titanium contains 36.8% iron, 31.6% titanium and 31.6% oxygen.

Determine the simplest whole number ratio for the moles of atoms.
[Ar values: Fe = 56; Ti = 48; O = 16]

 Fe Ti O A 1 1 1 B 1 1 2 C 1 1 3 D 4 3 1
10. Iron(III)hydroxide is a brown precipitate formed during the test for iron(III) ions.

FeCl3 (aq)  + 3NaOH (aq)  Fe(OH)3 (s)   +   3NaCl (aq)

What amount, in moles, of each reactant would be needed to produce 0.6 moles of iron(III)hydroxide?

 Moles of FeCl3 (aq) Moles of NaOH (aq) A 0.2 0.6 B 0.3 0.3 C 0.6 0.6 D 0.6 1.8