Chemical Change & Rate of Reaction (Cambridge (CIE) IGCSE Chemistry)

Exam Questions

10 hours71 questions
1a4 marks

In a set of experiments zinc was reacted with suphuric acid to form hydrogen. The apparatus below was used. 

6-1-q2a

The same mass of zinc was used each time. The volume of acid used was different each time. Use the syringe diagrams to record the volume of hydrogen produced each time in the table. Table of results  

6-1-q2a-table
1b4 marks

Plot the results on the grid below. Draw a smooth line graph.

6-1-q2b
1c1 mark

Use the graph to find the volume of sulphuric acid that will produce 33 cm3 of gas.

1d1 mark

What volume of gas is produced if 10 cm3 of sulphuric acid is used?

Did this page help you?

2a2 marks

Hydrochloric acid reacts with aqueous sodium thiosulfate to form a precipitate, which makes the solution turn cloudy. The formation of the precipitate can be used to show how fast the reaction proceeds, using the apparatus shown below.

6-1-q3a

A student used this method to investigate the effect of changing the concentration of the sodium thiosulfate solution on the speed of the reaction. The student used different concentrations of sodium thiosulfate solution. All other variables were kept the same.

Give two variables which were kept the same in the investigation.

2b1 mark

The results of the experiments are shown plotted on the grid below

6-1-q3b

Draw a line of best fit on the grid.

2c2 marks

Suggest two reasons why not all of the points lie on the line of best fit.

2d2 marks

From your graph, deduce the speed of reaction when the concentration of sodium thiosulfate is 0.075 mol/dm3. Show clearly on the graph how you worked out your answer.

2e2 marks

Explain why the speed of reaction increases when the concentration of sodium thiosulfate is increased.

2f1 mark

Sketch on the grid the line you would expect if the experiments were repeated at a higher temperature

Did this page help you?

3a4 marks

A student investigated the rate of reaction between magnesium ribbon and four different solutions of dilute sulfuric acid, A, B, C and D. The sulfuric acid was in excess in all experiments. Four experiments were carried out.

Experiment 1

Using a measuring cylinder, 30 cm3 of aqueous sulfuric acid A was poured into a beaker.

The stop clock was started and a 4 cm length of magnesium was added to the sulfuric acid in the beaker. The mixture was stirred constantly.

The time taken for all of the magnesium to react and disappear was measured. The beaker was rinsed out with distilled water.

Experiment 2

Experiment 1 was repeated using solution B of sulfuric acid.

Experiments 3 and 4

Experiment 1 was repeated, using solutions C and D of sulfuric acid.

Use the stop clock diagrams to record the times in the table. 

3474ee03-8524-45a3-955c-e3af6f3dc40c
3b4 marks

Plot the results for Experiments 1, 2, 3 and 4 on the grid and draw a smooth line graph.

4a8f6b03-667b-480b-b11f-4979803d1af6
3c4 marks

i) From your graph, deduce the concentration of the sulfuric acid if the time for the reaction was 80 s. Show clearly on the graph how you worked out your answer.

   .......................... mol/dm3

[2]

ii) From your graph, deduce how long the reaction would take if a solution of sulfuric acid of concentration 1.2 mol/dm3 was used. Show clearly on the graph how you worked out your answer.

.......................... s

[2]

3d1 mark

Why was the same amount of magnesium used in Experiments 1, 2, 3 and 4? 

3e2 marks

Another experiment was carried out.

A 4 cm length of magnesium ribbon was added to dilute sulfuric acid. The temperature of the solution was measured before and after the reaction. The observations were recorded and the gas given off tested.

Observations: Rapid effervescence and the tube felt hot. A lighted splint popped. Use the thermometer diagrams to record the temperatures.

5a058501-0bb8-4492-9b14-386778b05e60
3f4 marks

i) What type of chemical reaction occurred when magnesium reacted with sulfuric acid?

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

[1]

ii) Identify the gas given off. ..........................................................................

[1]

iii) Suggest the effect on the temperature change if this experiment was repeated using 2 cm of magnesium ribbon.

[2]

3g3 marks

Suggest a different method which could be used to investigate the rate of the reaction between magnesium and sulfuric acid.

State the difference in the apparatus used and measurements to be taken.

Apparatus: ...................................................................................................................................

Measurements: ..........................................................................................................................

Did this page help you?

4a4 marks

A teacher investigated the rate of a reaction between two solutions, J and K, and sulfuric acid at different temperatures.

 Four experiments were carried out.

Experiment 1 A large measuring cylinder was used to pour 50 cm3 of distilled water and 40 cm3  of sulfuric acid into a 250 cm3 conical flask.
A small measuring cylinder was used to add 2 cm3  of methyl orange and 5 cm3  of solution J to the mixture in the conical flask. The temperature of the mixture was measured.
The reaction was started by adding 5 cm3 of solution K to the conical flask, immediately starting the timer and swirling the mixture. The time taken for the mixture to turn pale yellow was measured. The final temperature of the mixture was measured.

Experiment 2

Experiment 1 was repeated but the mixture in the conical flask was heated to about 30 °C before adding the  solution K. The temperature of the mixture was measured. 5 cm3 of solution K was added to the conical flask. The timer was started and the mixture swirled. The time taken for the mixture to turn pale yellow was measured. The final temperature of the mixture was measured.

Experiment 3

Experiment 1 was repeated but the mixture in the conical flask was heated to about 40 °C before adding the  solution K to the flask. The same measurements were taken.

Experiment 4

Experiment 1 was repeated but the mixture in the conical flask was heated to about 50 °C before adding the solution K to the flask. The same measurements were taken. 

Use the stop-clock diagrams to record the times in the table.

Work out the average temperatures to complete the table.

6-1-q5a
4b4 marks

Plot the results on the grid and draw a smooth line graph.

6-1-q5b
4c2 marks

From your graph deduce the time taken for the mixture to turn pale yellow if Experiment 1 was repeated at an average temperature of 60 °C. Show clearly on the grid how you worked out your answer

4d3 marks

i) In which experiment was the rate of reaction greatest?

[1]

ii) Explain why the rate of reaction was greatest in this experiment.

[2]

4e4 marks

i) Suggest and explain the effect on the results of using a burette to measure the volume of solution J.

[2]

ii) Suggest and explain one other improvement to these experiments.

[2]

Did this page help you?

5a1 mark

Two experiments were carried out to show what factors affect the rate of decomposition of hydrogen peroxide, H2O2.
In each experiment the volume of gas produced was measured every minute for ten minutes.

Experiment 1

The student used a mixture of 50 cm3 of hydrogen peroxide, 50 cm3 of water and 1 g of manganese(IV) oxide at a room temperature of 20 °C. The results were plotted to obtain the graph shown.

Experiment 2

The student repeated Experiment 1 but did not record how much of each substance was used. The points were plotted on the grid.

873b6344-2ccf-4d8b-8a72-cf9362e5ac4a

Complete the graph for Experiment 2. 

5b4 marks

Suggest the composition of the mixture used in Experiment 2. Explain your suggestion.

Composition: ................................................................... Explanation: ....................................................................

5c1 mark

What is the function of the manganese(IV) oxide?

5d2 marks

Sketch on the grid the curve that you would expect if Experiment 1 was repeated at 10 °C.

Did this page help you?

6a4 marks

Two experiments using catalysts were carried out. Catalysts R and S were used to break down 50 cm3 of aqueous hydrogen peroxide at a temperature of 20 °C. The volume of oxygen given off was measured using the apparatus shown.

e932ad14-6a98-429c-9b86-5a1a8f24b3cb

Complete the table to show the volumes of gas measured in each experiment at the times shown in the table below.

89f33823-e11e-46b9-8a68-5029a8754e5c
6b6 marks

Plot a graph to show each set of results. Clearly label the graphs R and S.

820dd60b-1f95-4aa9-b74c-7238dacb0360
6c1 mark

Which result using catalyst R was inaccurate?

6d2 marks

Which is the better catalyst in this reaction? Explain your answer.

6e2 marks

Sketch a line on the grid to show the graph you would expect if the reaction with catalyst R was repeated at 50°C.

Did this page help you?

7a1 mark

Identical pieces of steel were placed in two different boiling liquids for 12 hours. The graphs show how the mass of each piece of steel changed.

cie-rates-graphs

Give one similarity in the change in mass of the steel in both liquids.

7b3 marks

Describe two ways in which the mass loss shown in graph A is different from that shown in graph B.

  1. ............................................................................................................................... ...............................................................................................................................

2. ............................................................................................................................... ...............................................................................................................................

7c2 marks

State two different safety precautions that would need to be taken when carrying out this investigation.

1. .......................................................................................................................................

2. .......................................................................................................................................

Did this page help you?

8a5 marks

A student investigated the speed of reaction when iodine was produced by the reaction of solution L with potassium iodide at different temperatures. Five experiments were carried out.

Experiment 1

A burette was filled with the aqueous solution L to the 0.0 cm3 mark.

10.0 cm3 of solution L was added from the burette into a boiling tube and the initial temperature of the solution was measured. Using a measuring cylinder, 5 cm3 of aqueous potassium iodide and 3 cm3 of aqueous sodium thiosulfate were poured into a second boiling tube. Starch solution was added to this boiling tube and the mixture shaken.

The mixture in the second boiling tube was added to the solution L, shaken and the clock started. These chemicals reacted to form iodine which reacted with the starch. When a blue colour appeared, the clock was stopped and the time measured and recorded in the table. The final temperature of the mixture was measured.

Experiment 2

Experiment 1 was repeated but solution L was heated to about 40 °C. The temperature of the solution was measured before adding the mixture in the second boiling tube. When a blue colour appeared, the clock was stopped and the time measured and recorded in the table. The final temperature of the mixture was measured.

Experiment 3

Experiment 2 was repeated, heating solution L to about 50 °C.

Experiment 4

Experiment 2 was repeated, heating solution L to about 60 °C.

Experiment 5

Experiment 2 was repeated, heating solution L to about 70 °C.

Use the thermometer diagrams in the table to record the temperatures and complete the table.

9c49d7f2-b210-4d4b-a581-1110a9247e24
8b5 marks

Plot the results on the grid below and draw a smooth line graph.

8cf558e8-02d0-4dcd-bbe3-96583e2f0962
8c2 marks

From your graph, work out the time taken for the blue colour to appear if solution L was heated to 80 °C. The final temperature of the reaction mixture was 64 °C. Show clearly on the grid how you obtained your answer.

8d1 mark

Suggest the purpose of the starch solution in the experiments.

8e3 marks

i) In which experiment was the reaction speed fastest?

[1]

ii) Explain, using ideas about particles, why this experiment was the fastest.

[2]

8f2 marks

Predict the effect on the time and speed of the reaction in Experiment 5 if it was repeated using a less concentrated solution of L.

Time: ..............................................................

Speed: .............................................................. 

8g1 mark

Why was a burette used to measure solution L instead of a measuring cylinder? 

Did this page help you?

9a5 marks

Dilute hydrochloric acid was added to excess calcium carbonate in a beaker as shown.

rates-of-reaction-mass-loss

The beaker was placed on a balance and the mass of the beaker and contents recorded every minute. The results are shown in the table.

mass of beaker and contents / g

184.0

178.0

175.6

174.6

174.0

174.0

time / min 

0

1

2

3

4

5

Plot the results on the grid and draw a smooth line graph.

graph-paper
9b2 marks

Use your graph to determine the mass of the beaker and contents after 30 seconds.

Show clearly on your graph how you worked out your answer.

9c1 mark

Why does the mass of the beaker and contents decrease?

9d1 mark

Suggest the purpose of the cotton wool.

9e1 mark

After how long did the reaction finish?

9f2 marks

A second experiment was carried out using hydrochloric acid at a lower temperature.

On the grid sketch a curve to show the expected results for this experiment.

Label this curve C.

Did this page help you?

10a4 marks

The speed of reaction between excess copper carbonate and dilute nitric acid was investigated using the apparatus below.

The temperature of the nitric acid was 20 °C.

1-1q4-diag

The volume of carbon dioxide produced was measured every minute for six minutes.

Use the gas syringe diagrams to complete the table of results.

1-1q4-table
10b4 marks

Plot the results on the grid below and draw a smooth line graph.

1-1q4-graph
10c2 marks

Which point appears to be inaccurate? Explain why.

10d2 marks

Sketch on the grid, the graph you would expect if the experiment was repeated using nitric acid at a temperature of 60°C.

Did this page help you?

11a1 mark

A student carried out an experiment to investigate the speed of reaction between sodium thiosulfate solution and dilute nitric acid. Sulfur is formed during this reaction and the mixture turns cloudy.

Experiment 1 method

Using a measuring cylinder, 100 cm3 of sodium thiosulfate solution was poured into a 250 cm3 beaker. The beaker was placed on a cross drawn on a piece of paper.

20 cm3 of dilute nitric acid was added to the beaker and the timer started.

screen-shot-2022-09-30-at-09-30-51

The time until the cross could not be seen was taken. The time was recorded in the table. 

Experiment 1 was repeated using different volumes of sodium thiosulfate as shown in the table. All experiments were carried out at 20 °C.

Table of results

screen-shot-2022-09-30-at-09-32-00

Why was the total volume of solution kept constant? 

11b1 mark

In Experiment 2, which is the last liquid to be added to the beaker? 

11c6 marks

i) Plot the results on the grid below. Draw a smooth line graph.

afce071c-b09f-48e7-ab0c-61bf0cc91454

[4] 

ii) Use your graph to work out the time taken for the cross to disappear when 55 cm3 of sodium thiosulfate solution and 45 cm3 of water were used. Indicate on the graph how you worked out your answer.

[2] 

11d2 marks

The experiments were repeated at 40 °C. Suggest how the results would differ. Explain your answer.

Did this page help you?

12a5 marks

A student investigated the effect of temperature on the speed of reaction between hydrochloric acid and aqueous sodium thiosulfate. When these chemicals react they form a precipitate, which makes the solution go cloudy. The formation of this precipitate can be used to show how fast the reaction proceeds, using the set up shown below.

screen-shot-2022-09-30-at-10-37-40

Five experiments were carried out.

Experiment 1

By using a measuring cylinder 50 cm3 of aqueous sodium thiosulfate was poured into a flask. The temperature of the solution was measured. The conical flask was placed on the printed text. 10 cm3 of hydrochloric acid was added to the flask and the timer started. The time taken for the printed text to disappear from view was recorded in the table. The final temperature of the mixture was measured.

Experiment 2

50 cm3 of aqueous sodium thiosulfate was poured into a conical flask. The solution was heated until the temperature was about 30 °C. The temperature of the solution was measured. 10 cm3 of hydrochloric acid was added to the flask and Experiment 1 was repeated.

The final temperature of the liquid was measured.

Experiment 3

Experiment 2 was repeated but the sodium thiosulfate solution was heated to about 40 °C before adding the hydrochloric acid.

The initial and final temperatures were measured.

Experiment 4

Experiment 2 was repeated but the sodium thiosulfate solution was heated to about 50 °C before adding the hydrochloric acid.

The initial and final temperatures were measured.

Experiment 5

Experiment 2 was repeated but the sodium thiosulfate solution was heated to about 60 °C before adding the hydrochloric acid.

The initial and final temperatures were measured. Use the thermometer diagrams to record all of the initial and final temperatures in the table.

Complete the table of results to show the average temperatures.

Table 1

screen-shot-2022-09-30-at-11-04-32
12b4 marks

Plot the results obtained on the grid and draw a smooth line graph.

screen-shot-2022-09-30-at-11-19-07
12c4 marks

i) In which experiment was the speed of reaction greatest?

[1]

ii) Explain why the speed was greatest in this experiment.

[3]

12d1 mark

Why was the same volume of sodium thiosulfate solution and the same volume of hydrochloric acid used in each experiment? 

12e4 marks

i) From your graph, deduce the time for the printed text to disappear if Experiment 2 was to be repeated at 70 °C. Show clearly on the grid how you worked out your answer.

[3]

ii) Sketch on the grid the curve you would expect if all the experiments were repeated using 50 cm3 of more concentrated sodium thiosulfate solution.

[1]

12f2 marks

Explain one change that could be made to the experimental method to obtain more accurate results.

Change: ................................................................

Explanation: .......................................................

Did this page help you?

138 marks

A catalyst is a substance that speeds up the rate of a chemical reaction and remains unchanged at the end of the reaction. Hydrogen peroxide solution, H2O2, breaks down to form oxygen. This decomposition is very slow if a catalyst is not used.

Plan an investigation to show that copper(II) oxide is a suitable catalyst for this reaction.

You can use aqueous hydrogen peroxide and common laboratory apparatus.

Step 1 Show that copper(II) oxide catalyses the decomposition of hydrogen peroxide and measure the rate of the reaction. 

Step 2 Show that the copper(II) oxide is unchanged at the end of the decomposition.

Did this page help you?

14a4 marks

The speed of reaction between excess magnesium and dilute hydrochloric acid was investigated using the apparatus below.

screen-shot-2022-09-30-at-13-11-55

The volume of hydrogen produced was measured every minute for six minutes.

Use the gas syringe diagrams to complete the table.

Table of results

screen-shot-2022-09-30-at-13-18-51
14b4 marks

Plot the results on the grid below. Draw a smooth line graph.

screen-shot-2022-09-30-at-13-36-22
14c1 mark

Why is the volume of gas given off the same at 5 minutes and 6 minutes? 

14d2 marks

Which point appears to be inaccurate? Explain why. 

14e2 marks

Sketch on the grid the graph you would expect if the experiment were repeated using the same volume of acid which was half as concentrated. 

Did this page help you?

15a3 marks

Hydrogen peroxide breaks down to form oxygen. The volume of oxygen given off can be measured using the apparatus below.

screen-shot-2022-09-30-at-14-31-37

Solids W and X both catalyse the breakdown of hydrogen peroxide. The syringe diagrams show the volume of oxygen formed every 20 seconds using these catalysts at 25 °C.

screen-shot-2022-09-30-at-14-31-42

Use the gas syringe diagrams to complete the table.

screen-shot-2022-09-30-at-14-31-52
15b6 marks

Plot a graph to show each set of results. Clearly label the curves.

screen-shot-2022-09-30-at-14-32-01
15c2 marks

Which solid is the better catalyst in this reaction? Give a reason for your choice.

Solid: .......................................................

Reason: ................................................. 

15d1 mark

Why is the final volume of oxygen the same in each experiment?

15e2 marks

Sketch a line on the grid to show the shape of the graph you would expect if the reaction with catalyst X was repeated at 40 °C. 

Did this page help you?

16a3 marks

Magnesium reacts with dilute sulphuric acid to form hydrogen gas. The speed of the reaction was investigated using the apparatus below.

screen-shot-2022-09-30-at-17-18-02

In an experiment 50 cm3 of dilute sulphuric acid was added to a large piece of magnesium. A student measured the total volume of gas produced at 2 minute intervals. Use the measuring cylinder diagrams to complete the table.

screen-shot-2022-09-30-at-17-18-13
16b3 marks

Plot the student’s results on the grid. Use the points to draw a smooth line graph.

screen-shot-2022-09-30-at-17-21-17
16c2 marks

i) At which time does the result appear to be inaccurate?

[1]

ii) Use the graph to deduce what the correct volume should be at this time.

[1]

Did this page help you?

17a2 marks

A student investigates the speed of reaction when aqueous hydrogen peroxide breaks down using a catalyst, manganese(IV) oxide. The catalyst remains unchanged at the end of the reaction. The apparatus was set up as shown in the diagram.

screen-shot-2022-10-03-at-09-30-00

Experiment 1
By using a measuring cylinder, 20 cm3 of hydrogen peroxide solution was poured into a conical flask. One spatula measure of manganese(IV) oxide was added to the flask, the bung was quickly put in the flask and the timer started.

The volume of gas collected in the measuring cylinder at 10 seconds, 20 seconds and 30 seconds was measured. The results are shown in the table below.

screen-shot-2022-10-03-at-09-30-09

Experiment 2

By using a measuring cylinder, 15 cm3 of hydrogen peroxide was poured into the conical flask. The instructions were repeated exactly as given for Experiment 1, but 5 cm3 of distilled water was also added to the flask.

Use the diagrams to record your results in the table below.

screen-shot-2022-10-03-at-10-18-36
17b2 marks

Experiment 3

Experiment 1 was repeated using 10 cm3 of hydrogen peroxide and 10 cm3 of distilled water. Record your results in the table.

screen-shot-2022-10-03-at-10-33-35
17c2 marks

Experiment 4

Experiment 1 was repeated using 5 cm3 of hydrogen peroxide and 15 cm3 of distilled water. Record your results in the table.

screen-shot-2022-10-03-at-10-38-49
17d5 marks

Plot your results on the grid for each Experiment. Draw 4 graphs and label each clearly with the number of the Experiment.

CIE IGCSE 6.1 Q18 graph
17e3 marks

i) Which experiment has the fastest rate of reaction?

[1] 

ii) Explain, in terms of particles, why this experiment has the fastest rate.

[2] 

17f4 marks

i) State two sources of error in the experiments.

1: .................................................................................................

2: .................................................................................................

[2]

ii) Suggest two improvements to reduce the sources of error in the experiments.

1: ..................................................................................................

2: ..................................................................................................

[2]

17g2 marks

State a practical method you could use to prove that manganese(IV) oxide was a catalyst in Experiment 1.

Did this page help you?

18a2 marks

An investigation into the reaction of calcium with water was carried out using the apparatus below. The temperature of the water increased during the experiment.

screen-shot-2022-10-03-at-11-48-16

The volume of hydrogen collected at one minute intervals was measured.

Use the diagrams to record the volumes in the table.

screen-shot-2022-10-03-at-11-48-23
18b3 marks

Plot the results on the grid. Join all of the results with a smooth curve.

CIE ICGSE 6.1 Q19
18c1 mark

What type of chemical reaction occurs when calcium reacts with cold water? 

18d4 marks

i)  Use the graph to describe how the speed of this reaction changes during the six minutes.

[2]

ii) Explain possible reasons for the changes in (d)(i).

[2]

Did this page help you?

196 marks

An aqueous solution of hydrogen peroxide decomposes very slowly to form oxygen. The speed of decomposition can be increased by using a catalyst. Two possible catalysts are the solids copper(II) oxide and chromium(III) oxide. Plan an investigation to find out which of these two oxides is the better catalyst for this decomposition. The space below can be used for a diagram. 

Did this page help you?

20a3 marks

A student investigated the speed of reaction between aqueous hydrochloric acid and marble chips (calcium carbonate). The apparatus below was used.

screen-shot-2022-10-03-at-13-20-42

5 test-tubes were put in a rack. To each test-tube was added 10 cm3 of different solutions of aqueous hydrochloric acid and a marble chip. The marble chips were the same size.

Experiment 1

By using a measuring cylinder 10 cm3 of the solution P of aqueous hydrochloric acid was placed in the first test-tube.

A marble chip was added and the volume of gas collected after two minutes was measured. Use the gas syringe diagram to record the volume.

screen-shot-2022-10-03-at-13-34-55

Experiment 2

Experiment 1 was repeated using solution Q of aqueous hydrochloric acid. Use the diagram to record the volume of gas collected in the table.

screen-shot-2022-10-03-at-13-35-00

Experiments 3, 4 and 5

Experiment 1 was repeated using the solutions R, S and T of aqueous hydrochloric acid in the third, fourth and fifth test-tubes.

Use the diagrams to record the volumes in the table.

Experiment 3

screen-shot-2022-10-03-at-13-40-31

Experiment 4

Experiment 4 CIE IGCSE 6.1 Q21

Experiment 5

Experiment 5 CIE IGCSE 6.1 Q21

Table of results

Experiment 

Solution of hydrochloric acid

Volume of gas collected / cm3

1

P

 

2

Q

 

3

R

 

4

S

 

5

T

 

20b4 marks

Plot your results on the grid. Draw a straight line graph.

screen-shot-2022-10-03-at-13-52-48
20c2 marks

Which result appears inaccurate? Give a reason for your choice.

Experiment: ..................................................................................

Reason: .......................................................................................... 

20d3 marks

i) Which experiment had the fastest rate of reaction?

[1]

ii) Suggest why this experiment was the fastest.

[2]

20e2 marks

How would the student know which of the reactants in the experiment was in excess? 

20f2 marks

i) State one possible source of error in the experiments.

[1]

ii) Suggest one improvement to reduce this source of error in the experiments.

[1]

Did this page help you?

216 marks

Is manganese(IV) oxide a catalyst?

A catalyst is a substance that speeds up a chemical reaction and remains unchanged.

Hydrogen peroxide, H2O2 breaks down to form oxygen. This reaction is very slow without a catalyst. Describe an experiment to show that manganese(IV) oxide is a catalyst for this reaction.

You are provided with the following items.

Hydrogen peroxide solution

Manganese(IV) oxide

Measuring cylinder

Balance

Beaker

Filtration apparatus

Splints / Bunsen burner

Distilled water

Did this page help you?

22a1 mark

The addition of calcium carbonate to excess dilute nitric acid produces carbon dioxide. The volume of carbon dioxide given off at 20 second intervals was recorded and plotted on the grid.

screen-shot-2022-10-03-at-19-35-56

Draw a smooth line graph on the grid.

22b2 marks

Circle the result which appears to be incorrect? Why have you selected this result? 

22c1 mark

Why does the reaction slow down? 

Did this page help you?

23a2 marks

A student carried out an experiment to investigate the speed of a reaction between sodium thiosulfate and dilute hydrochloric acid.

Na2S2O3 + 2HCl → 2NaCl + H2O + S + SO2

Experiment 1

By using a measuring cylinder, 50 cm3 of sodium thiosulfate solution was poured into a 100 cm3 beaker. The was placed on a cross drawn on a piece of paper. 10 cm3 of hydrochloric acid was added to the beaker and the timer started. 

screen-shot-2022-10-03-at-20-04-04

The time was taken until the cross could not be seen. The time was recorded in the table.

Experiments 2, 3, 4 and 5

Experiment 1 was repeated using different volumes of sodium thiosulfate as shown in the table. All experiments were carried out at 25 °C

Table of results 

screen-shot-2022-10-03-at-20-08-11

Why does the cross on the paper disappear? 

23b1 mark

Why was the total volume kept constant? 

23c1 mark

In which order should the water, hydrochloric acid and sodium thiosulfate solution be added to the beaker 

First: ................................................

Second: ................................................

Last: ................................................ 

23d7 marks

i)

Plot the results o the grid below. Draw a smooth line graph and label it 25 °C.

CIE ICGSE 6.1 Q24 Graph

[5] 

ii) Sketch on the grid the graph you would expect if the experiments were repeated at 50 °C. Label this graph.

[2] 

23e2 marks

The experiments were repeated using a 250 cm3 beaker instead of a 100 cm3 beaker. Suggest how the results would differ. Explain your answer. 

Did this page help you?

24a3 marks

An experiment was carried out using the apparatus below

screen-shot-2022-10-03-at-21-28-20

By using a measuring cylinder, 20 cm3 of hydrogen peroxide was placed was placed in the flask and 0.8 g of the catalyst, managnese(IV) oxide was added. The bung was replaced and the gas collected was measured at 1 minute intervals. The results were placed on the grid.

screen-shot-2022-10-03-at-21-28-29

i) Draw a smooth line on the grid.

[1] 

ii) Which of the results is inaccurate? Why have you chosen this result?

[2] 

24b1 mark

What mass of manganese(IV) oxide would remain at the end of the experiment? 

24c1 mark

What would be the effect of using a rubber connector with a hole in it. 

Did this page help you?

25a5 marks

A student investigated the speed of reaction between aqueous potassium bromate and potassium iodide solution. A burette was filled up to the 0.00 cm3 mark with aqueous potassium iodide. To each of 5 test-tubes was added 6 cm3 of aqueous potassium iodide to be used in the 5 following experiments.

Experiment 1

By using a measuring cylinder 12 cm3 of aqueous potassium bromate was poured into a small beaker. To this solution was added 4 cm3 of water, 2 cm3 of hydrochloric acid, 5 cm3 of starch solution and 1 cm3 of sodium thiosulphate solution.

The beaker was placed on a cross drawn on a piece of paper. From one of the test-tubes 6 cm3 of aqueous potassium iodide was added to the mixture in the beaker and the timer started. A dark blue colour formed. The timer was stopped when the cross on the paper could not be seen. Use the stop clock diagram to record the time in the table.

Experiment 2

By using a measuring cylinder 10 cm3 of potassium bromate solution was poured into a beaker. The instructions were repeated exactly as given for Experiment 1, but 6 cm3 of water was added to the beaker. Use the diagram to record the time in the table.

Experiments 3, 4 and 5

Experiment 1 was repeated using the volumes of aqueous potassium bromate and water specified in the table of results.

Record the times in the table.

Table of results 

CIE ICGSE 6.1 Q26 Table
25b4 marks

Plot the results on the grid. Draw a smooth line graph.

0ee01861-d7be-4153-bbe2-6eee6a33972c
25c3 marks

From your graph estimate the time of the reaction if Experiment 1 was repeated using 5 cm3 of potassium bromate and 11 cm3 of water.

Show clearly on your graph how you worked out your answers. 

25d3 marks

i) Which experiment is the quickest?

ii) Explain why this experiment is the quickest.

25e4 marks

i) State two possible sources of error in the experiments.

1:  ..............................................................................

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

2: ...............................................................................

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

ii) Suggest two improvements to reduce the sources of error in the experiments.

1: ................................................................................

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

2: ...............................................................................

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

Did this page help you?