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Year 10 Revision of Year 9 topics - higher
Q1.A student investigated the rate of reaction between sodium thiosulfate and dilute hydrochloric acid.
The student placed a conical flask over a cross on a piece of paper.
The student mixed the solutions in the flask. The solution slowly went cloudy. The student timed how long it took until the cross could not be seen.
The equation for the reaction is:
Na2S2O3(aq) + 2 HCl(aq) → 2 NaCl(aq) + H2O(l) + SO2(g) + S(s)
sodium
thiosulfate +
hydrochloric acid
→ sodium chloride
+ water + sulfur
dioxide + sulfur
(a) Explain why the solution goes cloudy.
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(b) The student repeated the experiment with different concentrations of sodium thiosulfate.
Concentration of
sodium thiosulfate in moles per dm3
Time taken until the cross could not be seen in seconds
Trial 1 Trial 2 Trial 3 Mean
0.040 71 67 69 69
0.060 42 45 45 44
0.080 31 41 33
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(i) Calculate the mean time for 0.080 moles per dm3 of sodium thiosulfate.
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Mean = ........................................ seconds (2)
(ii) Describe and explain, in terms of particles and collisions, the effect that increasing the concentration of sodium thiosulfate has on the rate of the reaction.
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Q2.Marble chips are mainly calcium carbonate (CaCO3).
A student investigated the rate of reaction between marble chips and hydrochloric acid (HCl).
Figure 1 shows the apparatus the student used.
Figure 1
(a) Complete and balance the equation for the reaction between marble chips and hydrochloric acid.
.................. + .................. → CaCl2 + .................. + .................. (2)
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(b) The table below shows the student’s results.
Time in s
Volume of gas
in dm3
0 0.000
30 0.030
60 0.046
90 0.052
120 0.065
150 0.070
180 0.076
210 0.079
240 0.080
270 0.080
On Figure 2:
• Plot these results on the grid. • Draw a line of best fit.
Figure 2
(4)
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(c) Sketch a line on the grid in Figure 2 to show the results you would expect if the experiment was repeated using 20 g of smaller marble chips.
Label this line A. (2)
(d) Explain, in terms of particles, how and why the rate of reaction changes during the reaction of calcium carbonate with hydrochloric acid.
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(e) Another student investigated the rate of reaction by measuring the change in mass.
Figure 3 shows the graph plotted from this student’s results.
Figure 3
Use Figure 3 to calculate the mean rate of the reaction up to the time the reaction is complete.
Give your answer to three significant figures.
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Mean rate of reaction = ........................................... g / s (4)
(f) Use Figure 3 to determine the rate of reaction at 150 seconds.
Show your working on Figure 3.
Give your answer in standard form.
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Rate of reaction at 150 s = ........................................... g / s (4)
(Total 20 marks)
Q3.The Sun produces helium atoms from hydrogen atoms by nuclear fusion reactions.
Hydrogen Helium
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(a) Describe the differences in the atomic structures of a hydrogen atom and a helium atom.
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(b) The Sun consists of 73% hydrogen and 25% helium. The rest is other elements. One of the other elements in the Sun is neon.
Use the Chemistry Data Sheet to help you to answer these questions.
(i) Complete the diagram to show the electronic structure of a neon atom.
(1)
(ii) Why is neon in the same group of the periodic table as helium?
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............................................................................................................... (1)(Total 5 marks)
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Q4.Plastic and glass can be used to make milk bottles.
The figure below shows the percentage of milk bottles made from glass between 1975 and 2010.
(a) Plot the points and draw a line on the figure above to show the percentage of milk bottles made from materials other than glass between 1975 and 2010.
(3)
(b) The table below gives information about milk bottles.
Glass milk bottle Plastic milk bottle
Raw materials Sand, limestone,
salt Crude oil
Bottle material Soda-lime glass HD poly(ethene)
Initial stage in production of bottle material
Limestone and salt used to produce
sodium carbonate.
Production of naphtha fraction.
Maximum temperature in production process
1600 °C 850 °C
Number of times bottle can be used for milk
25 1
Size(s) of bottle 0.5 dm3 0.5 dm3, 1 dm3, 2 dm3, 3
dm3
Percentage (%) of recycled material used in new bottles
50 % 10 %
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Evaluate the production and use of bottles made from soda-lime glass and those made from HD poly(ethene).
Use the information given and your knowledge and understanding to justify your choice of material for milk bottles.
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Q5.This question is about oil reserves.
(a) Diesel is separated from crude oil by fractional distillation. Describe the steps involved in the fractional distillation of crude oil.
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(b) Diesel is a mixture of lots of different alkanes. What are alkanes?
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(c) Petroleum products, such as petrol, are produced from crude oil. The graph shows the possible future production of petroleum products from crude oil and the expected demand for petroleum products.
Canada’s oil sands hold about 20% of the world’s known crude oil reserves.
The oil sands contain between 10 to 15% of crude oil. This crude oil is mainly bitumen.
In Canada the oil sands are found in the ground underneath a very large area of forest. The trees are removed. Then large diggers and trucks remove 30 metres depth of soil and rock to reach the oil sands. The oil sands are quarried. Boiling water is mixed with the quarried oil sands to separate the bitumen from the sand. Methane (natural gas) is burned to heat the water.
The mixture can be separated because bitumen floats on water and the sand sinks to the bottom of the water. The bitumen is cracked and the products are separated by fractional distillation.
Use the information given and your knowledge and understanding to suggest the advantages and disadvantages of extracting petroleum products from oil sands.
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........................................................................................................................ (6)(Total 11 marks)
The answers!
M1.(a) because sulfur / S forms 1
which is insoluble / a solid / a precipitate 1
(b) (i) 32
correct answer with or without working gains 2 marks
accept evidence of 31 + 33 / 2 for 1 mark
allow 35 for 1 mark 2
(ii) reaction rate increases
if incorrect reference to energy = max 2 1
because of more particles (per unit volume)
allow because particles are closer together 1
and because there is an increase in frequency of collisions
accept because particles are more likely to collide or higher chance of collision
ignore more (successful) collisions 1[7]
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M2.(a) CaCO3 + 2HCl → CaCl2 + H2O + CO2
2
allow 1 mark for correct formulae
(b) sensible scales, using at least half the grid for the points 1
all points correct
± ½ small square
allow 1 mark if 8 or 9 of the points are correct 2
best fit line 1
(c) steeper line to left of original 1
line finishes at same overall volume of gas collected 1
(d) acid particles used up
allow marble / reactant used up 1
so concentration decreases
allow surface area of marble decreases 1
so less frequent collisions / fewer collisions per second
do not accept fewer collisions unqualified 1
so rate decreases / reaction slows down 1
(e) mass lost of 2.2 (g) 1
time taken of 270 s
allow values in range 265 − 270 1
allow ecf for values given for mass and time 1
0.00815 (g / s)
or
8.15 × 10−3
allow 1 mark for correct calculation of value to 3 sig figs
accept 0.00815 or 8.15 × 10−3 with no working shown for 4 marks 1
(f) correct tangent 1
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eg 0.35 / 50 1
0.007
allow values in range of 0.0065 − 0.0075 1
7 × 10−3
1
accept 7 × 10−3 with no working shown for 4 marks [20]
M3.(a) hydrogen has one proton whereas helium has two protons
accept numbers for words
accept hydrogen only has one proton
ignore references to groups 1
hydrogen has one electron whereas helium has two electrons
accept hydrogen only has one electron
allow helium has a full outer shell (of electrons) 1
hydrogen has no neutrons or helium has two neutrons
if no other mark awarded, allow helium has more electrons / protons / neutrons for 1 mark
1
(b) (i) 2 electrons on first shell and
8 electrons on outer shell 1
(ii) they have a stable arrangement of electrons
accept they have full outer energy level / shell of electrons
do not accept they have the same number of electrons in their outer energy level / shell
allow they are noble gasesignore they are in group 0 1
[5]
M4.(a) all points correct
±1 small square
allow 1 mark for 6 or 7 plots 2
Year Percentage (%) of
bottles made from other materials
1975 5
1980 10
1985 22
1990 42
1995 70
2000 72
2005 90
2010 95
1
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(b) Level 3 (5–6 marks): A detailed and coherent argument is provided which considers a range of issues and comes to a conclusion consistent with the reasoning.
Level 2 (3–4 marks): An attempt to describe the advantages and disadvantages of the production and uses is made, which comes to a conclusion. The logic may be inconsistent at times but builds towards a coherent argument.
Level 1 (1–2 marks): Simple statements made. The logic may be unclear and the conclusion, if present, may not be consistent with the reasoning.
0 marks: No relevant content.
Indicative content
• glass – 2 stages in production of soda-lime glass • glass – second stage, heating sand, limestone and sodium carbonate • HDPE – 3 stages in production • HDPE – second stage, cracking of naphtha to obtain ethene • HDPE – third stage, polymerisation of ethene • fewer stages in glass production, may be quicker • higher temperature in glass manufacture, therefore maybe higher energy
requirement • glass bottle can be reused • consideration of collection / cleaning costs to reuse glass bottles • other glass products can be made from recycled glass • plastic has greater range of sizes • both produced from limited raw materials • higher percentage recycled materials in glass conserves raw materials
This indicative content is not exhaustive, other creditworthy responses should be awarded marks as appropriate.
6
[9]
M5.(a) heat to vaporise (the crude oil)
do not accept cracking / burning 1
vapours condense 1
at different temperatures
allow they have different boiling points 1
(b) (alkanes) are hydrocarbons or are compounds of hydrogen and carbon only 1
alkanes are saturated or have only (carbon-carbon) single bonds
accept have no (carbon-carbon) double bonds
accept general formula is CnH2n+2 for 2 marks 1
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(c) Marks awarded for this answer will be determined by the Quality of Written Communication (QWC) as well as the standard of the scientific response.
0 marksNo relevant content.
Level 1 (1-2 marks)There is a basic description of at least one advantage or one disadvantage of extracting petroleum products from oil sands.
Level 2 (3-4 marks)There is a clear description of an advantage and a disadvantage of extracting petroleum products from oil sands.
Level 3 (5-6 marks)There is a detailed description of both advantages and disadvantages of extracting petroleum products from oil sands.
Examples of the chemistry/environmental/economic/social points made in the response
Advantages:
• the oil sands are needed because crude oil is running out
• this crude oil is needed because demand is increasing
• the oil sands contain a large amount of crude oil
• the oil sands could improve Canada’s economy
• the oil sands provide employment for a lot of people
• the trees / forest are used for wood products / fuel
Disadvantages:
• destruction of environment / habitats
• fewer trees / forests to absorb carbon dioxide
• specified pollution, for example, visual, noise, atmospheric (including dust), water (including river or drinking) with cause, e.g. gases / particulates from burning diesel
• large amounts of methane (natural gas) are used to provide energy
• energy / fuel needed for cracking and fractional distillation
• burning fuel releases carbon dioxide
• crude oil / natural gas contains locked up carbon
• crude oil is non-renewable 6
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