1.6 Calculations Involving Masses
1.6 Calculations Involving Masses
1.6 Calculations Involving Masses
com
Questions
Q1.
The available apparatus includes a burette, a pipette, a funnel, a conical flask and an
indicator.
(a) State one safety precaution that must be taken when using sodium hydroxide solution
and dilute sulfuric acid.
(1)
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(b) The sodium hydroxide solution is made by dissolving 4.3 g of sodium hydroxide in water
and making the solution up to 250 cm3 with water.
Calculate the concentration of the solution in g dm−3.
(2)
(c) Write the balanced equation for the reaction of dilute sulfuric acid, H2SO4, with sodium
hydroxide.
(2)
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(d) The results of titrations to determine how much of an acid is required to neutralise a
given volume of an alkaline solution are shown in Figure 14.
Figure 14
Two of the titrations in Figure 14 should not be used to calculate the mean volume of
acid required.
Identify each titration and give a reason why it should not be used in the calculation of the
mean.
(2)
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Q2.
(ii) The equation for the reaction used in the extraction of iron is
Q3.
Figure 11 shows the apparatus that can be used to electrolyse sodium sulfate solution using
inert electrodes.
The sodium sulfate solution was made by dissolving 28.4 g of sodium sulfate in water to
make 250 cm3 of solution.
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Q4.
When copper sulfate solution reacts with sodium hydroxide solution, a precipitate of copper
hydroxide and a solution of sodium sulfate are formed.
The equation is
The copper sulfate solution had been prepared by dissolving 6.36 g of solid copper sulfate in
water and making the volume up to 250 cm3.
Q5.
3.14 g of solid copper sulfate was dissolved in water and made up to 250 cm3 of solution.
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Q6.
Q7.
In Figure 8, the letters A, E, G, J, X and Z show the positions of six elements in the periodic
table.
These letters are not the symbols of the atoms of these elements.
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Q8.
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Q9.
A titanium ore was analysed and found to contain 12 g of titanium atoms combined with 8.0
g of oxygen atoms.
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Q10.
A sample of CuSO4.5H2O was heated gently until all the water was removed to form
anhydrous copper sulfate, CuSO4.
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Q11.
Calculate, to one decimal place, the minimum mass of zinc that must be added to react with
all the copper sulfate.
(relative atomic mass: Zn = 65)
(2)
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mass = ........................................................... g
Q12.
In another stage, the pure titanium chloride, TiCl4 , is reacted with 500 moles of magnesium,
an excess.
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Q13.
Calculate the number of atoms combined in one mole of copper iodide, CuI2.
(Avogadro constant = 6.02 × 1023)
(2)
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Q14.
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Q15.
(i) Calculate the number of moles of this food colouring, C16H12N2O, in a 0.50 g sample.
(relative atomic masses: H = 1, C = 12, N = 14, O = 16)
(2)
(ii) Calculate the number of molecules in 2 moles of the food colouring, C16H12N2O.
(Avogadro constant = 6.02 × 1023)
(1)
Q16.
Calculate the number of moles of copper sulfate, CuSO4, in 50.00 cm3 of this solution.
(relative atomic masses: O = 16, S = 32, Cu = 63.5)
(3)
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Q17.
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Q18.
Calcium carbonate decomposes on heating to form calcium oxide and carbon dioxide.
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(ii) Calculate the atom economy for the formation of calcium oxide in this reaction.
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Q19.
Calculate the total number of atoms that combine to form 5.13 g of aluminium sulfate.
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Q20.
Calculate the total mass of the mixture after the precipitate has formed when these two
solutions are mixed together.
(1)
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Q21.
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Q22.
In one experiment, it was found that 4.48 g of iron reacted with excess lead nitrate solution
to form 24.84 g of lead.
Carry out a calculation, using the information above, to show which equation represents the
reaction taking place.
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Q23.
Answer the question with a cross in the box you think is correct . If you change
your mind about an answer, put a line through the box and then mark your new
answer with a cross .
The word equation for the reaction between copper carbonate and dilute sulfuric acid is
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(iii) What is the chemical test to show that a gas is carbon dioxide?
(1)
A bubble the gas through limewater, limewater turns cloudy
B put damp blue litmus paper in the gas, litmus paper turns red
C put a lighted splint into the gas, splint is extinguished
D measure the pH of the gas, pH = 4
Q24.
When copper sulfate solution reacts with sodium hydroxide solution, a precipitate of copper
hydroxide and a solution of sodium sulfate are formed.
The equation is
10 cm3 samples of copper sulfate solution were placed in five test tubes. Different volumes
of sodium hydroxide solution were added to these test tubes. The volumes of sodium
hydroxide solution added were 1 cm3, 2 cm3, 3 cm3, 4 cm3 and 5 cm3.
In each test tube a precipitate of copper hydroxide was formed. The precipitate was allowed
to settle and the height of the precipitate was measured with a ruler as shown in Figure 1.
Figure 1
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Figure 2
Q25.
A nickel sulfate solution is made by dissolving 23.5 g of nickel sulfate to make 250 cm3 of
solution.
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Q26.
Describe an experiment to determine the mass of oxygen that combines with a known mass
of magnesium, in a crucible and lid of known mass.
(3)
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Q27.
Determine the formula of this oxide of iron and use it to complete the balanced equation.
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Q28.
Q29.
Calcium carbonate decomposes on heating to form calcium oxide and carbon dioxide.
Another sample of calcium carbonate is heated and the mass of solid remaining is measured
each minute.
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(ii) It is impossible to be sure from this data that the reaction is complete.
State why.
(1)
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Q30.
Most metals are extracted from ores found in the Earth's crust.
The method used to extract a metal from its ore is linked to the reactivity of the metal.
Figure 14
Iron is extracted from iron oxide by heating the oxide with carbon.
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Q31.
B NH2SO2
C NH4SO4
D N2H8SO4
Q32.
Q33.
Answer the question with a cross in the box you think is correct . If you change
your mind about an answer, put a line through the box and then mark your new
answer with a cross .
Iron, when heated in air, reacts with oxygen to form iron oxide.
(ii) The equipment shown in Figure 7 can be used to find the mass of oxygen that combines
with iron.
Describe how the equipment shown in Figure 7 could be used to find the mass of oxygen
that combines with 0.500 g of iron wool in a crucible and lid of known mass.
(3)
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(Total for question = 4 marks)
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Q34.
(i) A beaker of barium chloride solution and a beaker of dilute sulfuric acid were placed on a
balance, as shown in Figure 6.
Figure 6
The dilute sulfuric acid was poured into the barium chloride solution and the beaker replaced
on the balance, as shown in Figure 7.
Figure 7
State the total mass reading on the balance after the reaction.
(1)
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(ii) Give the name of the white precipitate formed by the reaction of barium chloride solution
with dilute sulfuric acid.
(1)
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Q35.
When iron reacts with copper sulfate solution, solid copper is formed.
It was found that 10.00 g of iron powder reacted with excess copper sulfate solution to
produce 11.34 g of copper.
Carry out a calculation to decide which equation, A or B, represents the reaction taking
place.
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Q36.
Q37.
When heated, zinc carbonate decomposes to form zinc oxide and carbon dioxide gas.
Suggest how the student could confirm that the decomposition was complete.
(3)
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Q38.
Answer the question with a cross in the box you think is correct . If you change
your mind about an answer, put a line through the box and then mark your new
answer with a cross .
(ii) What type of reaction occurs when chromium reacts with oxygen?
(1)
A condensation
B evaporation
C neutralisation
D oxidation
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Mark Scheme
Q1.
Q2.
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Edexcel Chemistry GCSE - Calculations involving masses PhysicsAndMathsTutor.com
Q3.
Q4.
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Q5.
Q6.
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Q7.
Q8.
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Q9.
Q10.
Q11.
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Q12.
Q13.
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Q14.
Q15.
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Q16.
Q17.
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Q18.
Q19.
Q20.
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Q21.
Q22.
Edexcel Chemistry GCSE - Calculations involving masses PhysicsAndMathsTutor.com
Q23.
Q24.
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Q25.
Q26.
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Q27.
Q28.
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Q29.
Q30.
Edexcel Chemistry GCSE - Calculations involving masses PhysicsAndMathsTutor.com
Q31.
Q32.
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Q33.
Q34.
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Q35.
Q36.
Edexcel Chemistry GCSE - Calculations involving masses PhysicsAndMathsTutor.com
Q37.
Q38.