(1)jtaylor.teacher.edutronic.net/wp-content/uploads/sites/...q1. limestone is used to make cement....

Q1. Limestone is used to make cement.

(a) When cement is made, limestone is strongly heated.

Limestone is mainly calcium carbonate.

The equation shows what happens when 500 kg of calcium carbonate (CaCO3) is strongly

heated.

(i) What is the chemical name of CaO?

............................................................................................................... (1)

CaCO3

CaO + CO2

500 kg 280 kg

(ii) What is the mass of carbon dioxide (CO2) produced in this reaction?

Draw a ring around the correct answer.

(1)

220 kg 500 kg 780 kg

(b) Which of these building materials is made when cement is mixed with sand?


(1)

clay mortar stone

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(c) Cement is used to make concrete.

A student investigated the strength of 1 kg concrete blocks.

The student used different masses of cement to make each concrete block.

The diagram shows the apparatus the student used to test the strength of the 1 kg concrete blocks.

The student tested each concrete block by adding masses until the block broke.

The student’s results are shown below in the table.

(i) Give two conclusions using the data from the table above.

...............................................................................................................

...............................................................................................................

...............................................................................................................

............................................................................................................... (2)

Mass of cement in g Mass needed to break

the block in kg

200 1.2

300 2.7

400 3.7

500 4.2

600 4.5

700 4.6

800 4.6

900 4.6

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(ii) Suggest one way the student could improve the investigation.

...............................................................................................................

............................................................................................................... (1)

(Total 6 marks)

Q2. Limestone is mainly calcium carbonate.

(a) Limestone is used to make cement.

What is added to limestone to make cement?


(1)

aggregate clay mortar sand

(b) Manufacturing cement from 1000 kg of limestone produces a total of 800 kg of carbon dioxide.

One of the reactions in manufacturing cement is the thermal decomposition of calcium carbonate.

The equation shows what happens when 1000 kg of calcium carbonate decomposes to form 560 kg of calcium oxide at 1500 °C.

CaCO3

CaO + CO2

(i) How much carbon dioxide is produced when 1000 kg of calcium carbonate is completely decomposed?

...............................................................................................................

............................................................................................................... (1)

(ii) Suggest why the total amount of carbon dioxide produced by the manufacturing process is greater than your answer to part (i).

...............................................................................................................

............................................................................................................... (1)

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(c) Cement and sand are used to make concrete.

A student made some 1 kg concrete blocks.

The student varied the percentage of cement in the mixture.

The student tested the strength of the concrete blocks by hanging masses from the block, as shown in Figure 1, until the block broke.

Figure 2 shows the student’s results.

Give two conclusions that can be made from these results.

........................................................................................................................

........................................................................................................................

........................................................................................................................

........................................................................................................................ (2)

(Total 5 marks)

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Q3. The picture shows a limestone quarry.

By Thomas Bjørkan (Own work) [CC-BY-SA-3.0], via Wikimedia Commons

(a) Local residents were against the opening of a new limestone quarry. The quarry was estimated to have a 10-year operating period.

The quarry company gave reasons to show how the quarry could benefit local residents over the next 10 to 15 years.

Suggest one economic and one environmental reason the quarry company could give.

Economic reason ...........................................................................................

........................................................................................................................

Environmental reason ....................................................................................

........................................................................................................................ (2)

(b) What happens when limestone (calcium carbonate) is heated?

Include in your answer:

• the chemical names of the substances produced

• the name of the process.

........................................................................................................................

........................................................................................................................

........................................................................................................................

........................................................................................................................ (2)

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(c) (i) Lime is calcium oxide. Calcium oxide reacts with water to form calcium hydroxide, Ca(OH)

2

Write the symbol equation for this reaction.

............................... + ............................... → ............................... (2)

(ii) Name the gas that a solution of calcium hydroxide in water is used to test for.

Give the result that you would see if the gas was present.

........................................................................................................................

........................................................................................................................

........................................................................................................................

........................................................................................................................ (2)

(Total 8 marks)

Q4. Limestone and the products of limestone have many uses.

(a) Limestone is quarried.

Photograph © Lonny Kalfus / Getty Images

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Quarrying limestone has impacts that cause environmental problems.

Tick ( ) two impacts that cause environmental problems.

(2)

Impact of quarrying Tick ( )

Puts off tourists

Causes dust pollution

Increases jobs

Increases traffic

(b) Limestone contains calcium carbonate, CaCO3. When it is heated calcium carbonate

produces calcium oxide and carbon dioxide.

The word equation for this reaction is:

calcium carbonate → calcium oxide + carbon dioxide

(i) Complete the sentence.

The reaction when calcium carbonate is heated is called

thermal ........................................... (1)

(ii) 100 g of calcium carbonate was heated and produced 56 g of calcium oxide. Calculate the mass of carbon dioxide produced.

...............................................................................................................

....................................... g (1)

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(c) The flow chart shows the stages in the limestone cycle.

Complete the names of the calcium compounds formed in the flow chart.

(2)

(Total 6 marks)

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Q5. In the UK, railway sleepers are often made from concrete.

A scientist was asked to find the best concrete mixture to use so that railway sleepers would not break easily.

The scientist made:

• a mould to make small models of concrete sleepers

• concrete mixtures using crushed rock, sand, cement and water

• the equipment shown to add 0.1 kg masses until the model sleeper broke.

The scientist’s results are shown in the table.

(a) (i) Calculate the mean total mass added to break the model sleeper that has 20% cement by volume.

...............................................................................................................

Mean = ........................... kg (1)

Concrete mixture in % by volume

Total mass added to break the model sleeper in kg

Cement Sand Crushed

rock Test 1 Test 2 Test 3 Mean

10 70 20 1.1 1.3 1.2 1.2

20 60 20 2.6 2.5 2.4

30 50 20 3.3 3.3 3.3 3.3

40 40 20 3.8 4.0 3.3 3.9

50 30 20 4.5 4.2 4.3 4.3

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(ii) Choose one result in the table that the scientist should check and test again.

Result: % cement by volume ....................... Test number .......................

Explain why you chose this result.

...............................................................................................................

............................................................................................................... (2)

(iii) What is the relationship between the total mass to break the model sleeper and the percentage (%) of cement by volume in the concrete mixture?

...............................................................................................................

............................................................................................................... (1)

(iv) Suggest one other variable that the scientist should have recorded in the table of results.

............................................................................................................... (1)

(b) The scientist thought that full-size railway sleepers should be made from 30% cement, 50% sand and 20% crushed rock.

What other information about these three materials is needed before the scientist recommends using this mixture to make a full-size railway sleeper?

........................................................................................................................

........................................................................................................................

........................................................................................................................

........................................................................................................................ (2)

(Total 7 marks)

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M1. (a) (i) calcium oxide

allow quicklime 1

(ii) 220 kg 1

(b) mortar 1

(c) (i) the greater the mass of cement the stronger the block / concrete (initially) allow the greater the mass of cement, the greater the mass needed to break the block / concrete (initially)

1

above 700 g an increase in mass of cement has no extra effect on the strength of the block / concrete

allow above 700 g the mass needed to break the block / concrete remains the same accept for 2 marks as mass of cement increases, the (rate of) increase in strength of the block / concrete decreases or increase in mass needed to break block / concrete decreases as mass of cement increases

1

(ii) any one from: • repeat the investigation and calculate a mean

allow average for mean • use smaller intervals.

ignore references to accuracy, precision, range 1

[6]

M2. (a) clay 1

(b) (i) 440 kg 1

(ii) burning of (fossil) fuels (to provide energy) allow (produced from) other compounds in limestone

1

(c) increase in strength of concrete is less with increasing percentage of cement allow for one mark: as the percentage of cement increases, the strength of concrete increases. allow for one mark: increase in mass needed to break block / concrete decreases as mass of cement increases.

2 [5]

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M3. (a) economic

any one from: • increases jobs • more money in local economy • increase in local trade • more shops / businesses • better transport links

1

environmental

any one from: • future development of quarry eg to lake / reservoir • future development to recreational area • provides different habitat

1

(b) calcium oxide and carbon dioxide both products required for mark allow CaO for calcium oxide allow CO

2 for carbon dioxide

allow quicklime for calcium oxide 1

(thermal) decomposition 1

(c) (i) CaO + H2O → Ca(OH)

2

correct formulae 3 correct for 2 marks 2 correct for 1 mark ignore attempts to balance equation

2

(ii) carbon dioxide 1

solution goes cloudy (then clear again) accept milky / forms a white precipitate

1 [8]

M4. (a) causes dust pollution 1

increases traffic 1

(b) (i) decomposition 1

(ii) 44(g) 1

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(c) (calcium) hydroxide 1

(calcium) carbonate 1

substances must be in the order shown [6]

M5. (a) (i) 2.5(kg)

ignore units 1

(ii) 40% (cement) and Test 3

ignore units 1

because it is anomalous or because it is much lower than the other two readings

accept value not used to calculate mean ignore outlier

1

(iii) as the percentage of cement increases the mass needed to break the sleeper increases

allow ‘strength’ for ‘mass needed’ allow correct relationship using percentage of sand

1

(iv) volume/percentage / amount of water accept temperature

1

(b) any two from:

• availability (of the raw materials)

• cost of the raw materials

• purity (of the raw materials) 2

[7]

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