rts chemistry spm question bank chapter 10

8/14/2019 RTS Chemistry SPM Question Bank Chapter 10

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Essential Chemistry SPM Question Bank

Chapter 10: Rate of Reaction

Paper 1

1)

The above diagram is the energy profile diagram for an exothermic reaction. Among A,B, Cand D, which represents the activation energy of the reaction?

2) Which of the following explains why the rate of hydrogen released decreases with time?

Zn + 2HClZnCl2+ H2

I Mass of zinc decreases

II Mass of zinc chloride increasesIIIConcentration of acid decreases

IVVolume of acid decreasesA III only C I and III onlyB I and II only D I, III and IV only

3) Which of the following acids produces the highest initial rate of reaction if 6 g of calciumcarbonate is put into it?

A 50 cm3of 0.5 mol dm

-3hydrochloric acid

B 50 cm3of 1 mol dm

-3sulphuric acid

C 50 cm3of 1 mol dm

-3hydrochloric acid

D 100 cm3of 5 mol dm

-3ethanoic acid

4) GraphPin the diagram below is obtained from the reaction between 5 g of zinc powder(in excess) and 50 cm3of 2 mol dm-3hydrochloric acid.

Progress of reaction

A

B

D

C50

Energy / kJ

100

170

Volume of gas / cm3

Time /s

P

Q


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Which of the following are probably the reactants that produce graph Q?

A 5 g of zinc pieces and 50 cm3of 2 mol dm

-3hydrochloric acid

B 6 g of zinc powder and 50 cm3of 1 mol dm

-3hydrochloric acid

C 6 g of zinc pieces and 100 cm3of 1 mol dm

-3hydrochloric acid

D 5 g of zinc pieces and 100 cm3of 2 mol dm

-3hydrochloric acid

5) The diagram below is the energy profile diagram of a reaction.

Which of the following changes the activation energy from Ea to Eb?

A Concentration C CatalystB Temperature D Total surface area

6) Graph I in the diagram below shows the graph of volume of gas against time for thereaction between 6 g of zinc pieces and 50 cm

3of 1 mol dm

-3sulphuric acid.

Which of the following must be done to produce Graph II?

A Cool the sulphuric acid

B Add 10 cm3of 0.5 mol dm

-3sulphuric acid

C Replace the zinc pieces with zinc powderD Add copper(II) sulphate solution

P + Q

R + S

Progress of reaction

Ea

50

Energy / kJ

100

170

Eb

Volume of gas / cm3

Time /s

II

I


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7) Which of the following shows correctly the graph of concentration of solution against

rate of reaction for the reaction between sodium thiosulphate solution and dilutehydrochloric acid?A C

B D

8) The diagram below shows the graph of volume of gas against time for the reactionbetween calcium carbonate and dilute hydrochloric acid.

What is the mass of calcium carbonate that reacts with the acid in this experiment?[Relative formula mass: CaCO3= 100; Molar volume = 24 dm

3mol

-1at room condition]

A1 g C 20 g

B10 g D 24 g

9) The reaction between dilute nitric acid and zinc produces hydrogen. This reaction iscompleted within 60 seconds and the maximum volume of gas released is 120 cm

3.

Calculate the average rate of reaction.A 0.5 cm

3s

-1C 1.5 cm

3s

-1

B 1.0cm3s

-1D2.0 cm

3s

-1

Concentration

Rate of

reaction

Concentration

Rate of

reaction

Concentration

Rate of

reaction

Concentration

Rate of

reaction

Volume of gas / cm3

Time /s

240


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10) Which of the following is a characteristic of a catalyst?

A Specific in its reactionB Influences the amount of productC The chemical property of catalyst changes at the end of the reactionD A lot of catalysts are needed to influence the rate of reaction

Paper 2

Structured question

Two experiments are conducted to study the effect of a catalyst on the rate of reaction betweenmarble chips and hydrochloric acid.

Experiment I 10 g of zinc pieces (in excess) and 50 cm of 0.2 mol dm-

hydrochloric acid

Experiment II 10 g of zinc pieces (in excess), 50 cm of 0.2 mol dm-

hydrochloric acid and

2 cm3of copper(II) sulphate solution

(a) Write the chemical equation to show the reaction that occurs.(b) What is the role of copper(II) sulphate solution in this experiment?(c) Sketch the graph of volume of gas collected against time for both experiments on the same

axes.

(d) (i) In which experiment is the rate of reaction between zinc and hydrochloric acid higher?(ii) Explain your answer in (d)(i) based on the collision theory.

(e) Calculate the maximum mass of zinc that reacts in this experiment.[Relative atomic mass: Zn = 65]

(f) State threeother factors besides the catalyst that affects the rate of reaction in thisexperiment.

Volume of gas

Time


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Essay question(a) Porridge that is stored in a refrigerator will last longer than porridge that is placed on the

dining table. Explain this statement.[4 marks]

(b) Three experiments had been carried out to investigate the factors affecting the rate ofreaction. The table below shows the reaction condition for each of the experiments.

Experiment ReactantsI Excess zinc pieces and 25 cm of 0.1 mol dm

-hydrochloric acid

II Excess zinc pieces and 25 cm of 0.2 mol dm-

hydrochloric acidIII Excess zinc powder and 25 cm 0.2 mol dm

-hydrochloric acid

(i) Sketch the graph of volume of gas collected against the time for Experiments I, II and III,using the same axes. [3 marks]

(ii) The chemical equation below shows the reaction between zinc and hydrochloric acid.Zn + 2HClZnCl2+ H2

Given that the relative atomic mass of H = 1, Cl = 35.5, Zn = 65, and the molar volume of

any gas is 24 dm3 mol-1at room temperature and pressure, calculate the maximum volume ofhydrogen produced in Experiment I. [4 marks]

(c) Calculate the average rate of reaction for Experiment I if the maximum volume of hydrogenis collected in 120 seconds. [2 marks]

(d) Based on the graph drawn in (b)(i), compare the rate of reaction between Experiment II and

Experiment III. Explain the difference in the rate of reaction with reference to the collisiontheory. [4 marks]

(e) The rate of reaction in Exper iments I, II and III can be increased by adding copper(II)sulphate solution. Explain the role of copper(II) sulphate solution based on the collisiontheory. [3 marks]

Paper 3

Based on the situation above, plan an experiment to investigate the effect of reactant size on therate of reaction between a named metal and a named acid.Your plan must include the following items:

(i) Aim of experiment [State the aim of the experiment](ii) All the variables [State the hypothesis](iii) Lists of materials and apparatus [List the materials and apparatus](iv) Procedure [Choose the procedure](v) Tabulat ion of data [Tabulate the data]

A small piece of charcoal is easier to light as compared with a big

piece of charcoal.


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Answers

Paper 1

1 A

2 C3 B

4 D5 C

6 A7 B

8 A9 D

10 A

Paper 2

Structured question(a) Zn + 2HClZnCl2+ H2(b) To increase the rate of reaction(c)

(d) (i) Experiment II(ii) Copper(II) sulphate (catalyst) provides an alternative route that requires a loweractivation energy. With a lower activation energy, more particles will have effectivecollisions.(e)

0.005 mol 0.01mol

Zn(s) + 2HCl(aq) ZnCl2(aq) + H2(g)? g V =50 cm3

M = 0.2 mol dm-3

MV = number of moles1000

0.2 x 50 = 0.01 mol

1000Number of moles of HCl = 0.01 mol1 mol of Zn reacts with 2 mol of HCl0.01/2 = 0.005 mol of Zn reacts with 0.01 mol of HCl

Number of moles of Zn = 0.005 molTherefore, mass of Zn= 0.005 x 65 = 0.325 g

(f) Temperature of reaction, size of zinc and concentration of hydrochloric acid

Volume of gas / cm3

Time /s

I

II


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Essay question(a)- Bacteria is active at room temperature- Bacteria carry out biochemical processes- Bacteria produce toxins

- The rate of food decay is higher at room temperature

(b)(i)

(ii)

0.0025 mol 0.00125 mol

Zn(s) + 2HCl(aq) ZnCl2(aq) + H2(g)V = 25 cm

3

M = 0.1 mol dm-3

MV = number of moles1000

0.1 x 25 = 0.0025 mol1000

Number of moles of HCl = 0.0025 mol

2 mol of HCl produces 1 mol of H20.0025 mol of HCl produces 0.0025/2 = 0.00125 mol of H 2

Number of moles of H2= 0.00125 molTherefore, volume of H2= 0.00125 x 24000 = 30 cm

3

(c) Average rate of reaction = 30 = 0.25 cm3s

-1

120(d) - The rate of reaction in Experiment III is higher

- The total surface area of zinc in Experiment III is larger

- The collision frequency between zinc particles and hydrogen ion increases- The effective collision frequency increases

(e) - Copper(II) sulphate solution acts as a catalyst- The catalyst lowers the activation energy- Effective collision frequency increase

Time / s

Volume of gas

I

II

III


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Paper 3(i) To study the effect of the reactant size on the rate of reaction(ii) Variable that is manipulated: Size of the zinc

Variable that responds: Rate of reactionVariable that is f ixed: Volume and concentration of the hydrochloric acid / mass of the zinc

(iii) Material: 1 mol dm-3

of hydrochloric acid, 2 g of zinc pieces, 2 g of zinc powder

Apparatus: Measuring cylinder, conical flask, stopwatch(iv) - 25 cm

3of 1 mol dm

-3hydrochloric acid is measured and poured into the conical

flask- 2 g of zinc pieces is put into the hydrochloric acid- The stopwatch is started immediately- The mixture of substances is shaken slowly- The time taken for all the zinc pieces to dissolve is recorded- The experiment is repeated using zinc powder- The volume and concentration of hydrochloric acid and the mass of zinc used are

the same(v)

Size of zinc Time taken /s

Zinc piecesZinc powder

rts chemistry spm question bank chapter 10

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