GCSE AQA Chemistry Reactions of Acids: Limestone is used to make many d

Question

Limestone is used to make many different materials.

2 (a) Heating limestone produces calcium oxide and carbon dioxide.

Complete the sentences.

2 (a) (i) The main compound in limestone is calcium .............................................................. .

2 (a) (ii) The reaction to produce calcium oxide from limestone is thermal .............................. .

2 (a) (iii) Calcium hydroxide is produced when calcium oxide reacts with ...................................... .

2 (a) (iv) Calcium hydroxide is used to neutralise acids because it is an ......................................... .

2 (b) Cement is made from limestone and clay.

Concrete is made by mixing cement with water, sand and aggregate (small pieces of rock).

A group of students did an investigation on the amount of aggregate needed to make the strongest concrete beam.

The students used this method:
- use the same mass of cement and the same mass of sand but change the mass of aggregate to make seven different concrete mixtures
- use the different concrete mixtures to make beams of the same size
- add weights, as shown in Figure 2, until concrete beam breaks.

Figure 2
The concrete beam.

The students’ results are plotted on the graph in Figure 3.

Figure 3
Plot of the students’ results.

2 (b) (i) One of the points is anomalous.

Complete the graph in Figure 3 by drawing two straight lines of best fit.

2 (b) (ii) Describe one way the students could improve the method so that their results are more accurate for each graph point.

2 (b) (iii) What force is needed to break a concrete beam containing no aggregate?

Show your working on the graph.

2 (b) (iv) One of the students concluded that:

‘The force needed to break a concrete beam increases as the mass of aggregate increases.’

The student’s conclusion is not completely correct. Use values from the graph to explain why.

Limestone is used to make many different materials - AQA - GCSE Chemistry - Question 2 - 2015 - Paper 1

Worked Solution & Example Answer:Limestone is used to make many different materials - AQA - GCSE Chemistry - Question 2 - 2015 - Paper 1

2 (a) (i) The main compound in limestone is calcium

2 (a) (ii) The reaction to produce calcium oxide from limestone is thermal

2 (a) (iii) Calcium hydroxide is produced when calcium oxide reacts with

2 (a) (iv) Calcium hydroxide is used to neutralise acids because it is an

2 (b) (i) One of the points is anomalous.

2 (b) (ii) Describe one way the students could improve the method.

2 (b) (iii) What force is needed to break a concrete beam containing no aggregate?

2 (b) (iv) The student’s conclusion is not completely correct.

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