Tuesday, September 9, 2008

rate of reaction

1. The collisions that are successful in producing a chemical reaction are called

A effective collisions

B ineffective collisions

C successful collisions

D unsuccessful collisions

2. Which of the following alters the rate of a chemical reaction but remains chemically unchanged at the end of a reaction?

A Product

B Catalyst

C Reactant

3. The number of collisions per second that will result in a reaction is known as

A collision theory

B effective collision

C effective collision frequency

D ineffective collision frequency




4. Which of the following statement is true about the collision theory?

A All collisions produce a reaction.

B The increase in the activation energy will increase the rate of reaction.

C The increase in the effective collision frequency will increase the rate of reaction.

D The increase in the effective collision frequency will increase the quantity of the product formed.

5. Which of the following does not affect the rate of a reaction?

A Temperature

B Size of a reactant

C Volume of solution

D Concentration of solution

6. Which of the following is not the characteristic of catalyst?

A Are specific in their actions.

B Increase the quantity of products.

C Do not change chemically after a reaction.

D Are required in small amount to affect the rate of reaction.


7. The equation shows the reaction between calcium carbonate and dilute hydrochloric acid.

CaCO3 (s) + 2HCl (aq) CaCl2 (aq) + H2O (l) + CO2 (g)

After 60 seconds, the volume of gas produced is 85 cm3. Calculate the average rate of reaction in the unit of cm3s-1.

A 0.71

B 1.42

C 25.00

D 5100.00

8. When the concentration of a solution increases, the rate of reaction also increases.

Which of the following solutions will produce the highest rate of reaction between magnesium and dilute hydrochloric acid?

A 50 cm3 of 0.10 moldm-3 HCl

B 50 cm3 of 0.15 moldm-3 HCl

C 50 cm3 of 0.20 moldm-3 HCl

D 50 cm3 of 0.25 moldm-3 HCl

9. Which of the following is true?


Catalyst

Process

A

Iron

Ostwald process for producing nitric acid

B

Vanadium(V) oxide

Contact process for producing sulphuric acid

C

Platinum

Haber process for producing ammonia

D

Nickel

Cracking process for producing alkane and alkene.

10. Which of the following has the highest rate of reaction?


Reaction

Time taken

A

Combustion of magnesium in oxygen

30 seconds

B

Photosynthesis

1 day

C

Fermentation

2 days

D

Rusting of iron

3 days

11. Which of the following is incorrect about rate of reaction?

A An increased in pressure decreases the rate of reaction.

B The smaller the size of the solid particles, the higher the rate of reaction.

C The higher the concentration of the reactant, the higher the rate of reaction.

D The rate of reaction increases if the temperature of the reactants is increased.


12. Which of the following reactions will be affected by the changes in pressure?

A 2H2O2 (aq) → 2H2O (l) + O2 (g)

B N2 (g) + 3H2 (g) 2NH3 (g)

C Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2 (g)

D CaCO3 (s) + 2HCl (aq) CaCl2 + H2O (l) + CO2 (g)

13. Sulphur is precipitated when sodium thiosulphate solution is added with dilute hydrochloric acid in a conical flask. The rate of precipitation of sulphur can be increased by

A using a bigger conical flask.

B stirring the reaction mixture.

C heating the reaction mixture.

D adding water to increase the volume of mixture.

14. Why is food cut into small pieces before cooking

A The food can be stirred easily.

B The total pieces of food are more.

C The total surface area of the food is larger.

D The food can be cooked at a higher temperature.

15. The equation shows the reaction between calcium carbonate and dilute hydrochloric acid.

CaCO3 + 2HCl → CaCl2 + CO2 + H2O

Based on the equation, which one of the following changes can be used to determine the rate of reactions in the above reaction?

A Increase in the mass of calcium carbonate.

B Increase in the concentration of hydrochloric acid.

C Decrease in the concentrarion of calcium chloride.

D Increase in the volume of carbon dioxide is produced.

16. The equation shows the reaction to produce hydrogen gas.

H2SO4 + Zn → ZnSO4 + H2

Which of the following would increase the rate of production of hydrogen gas?

A Increase the volume of acid.

B Increase the size of zinc granules.

C Increase the atmospheric pressure.

D Increase the temperature of the mixture.


17. The reaction between hydrochloric acid and zinc produces hydrogen gas. In an experiment, a maximum volume of 48.0 cm3 of hydrogen gas is produced in 120 s.

What is the average rate of the reaction?

A 0.2 cm3s-1

B 0.4 cm3s-1

C 1.8 cm3s-1

D 2.5 cm3s-1

18. Three experiments are conducted to compare the rate of a reaction. The results of the experiments are shown below:

Experiment

Reactants

Rate of reaction

I

2 g of magnesium ribbon with 10 cm3 of 1.0 moldm-3 hydrochloric acid.

p

II

2 g of magnesium ribbon with 10 cm3 of 2.0 moldm-3 hydrochloric acid.

q

III

2 g of powdered magnesium with 10 cm3 of 2.0 moldm-3 hydrochloric acid.

r

Arrange the rate of reaction for the three experiments according to increasing order.

A p, q, r

B r, p, q

C r, q, p

D q, r, p

19. The table shows the total volume of gas collected at regular intervals in a reaction.

Time(s)

0

30

60

90

120

150

180

210

Volume of gas(cm3)

0.0

4.0

7.4

10.4

12.8

14.6

17.2

17.2

What is the average rate of reaction in the second minute?

A 0.080 cm3s-1

B 0.090 cm3s-1

C 0.107 cm3s-1

D 0.133 cm3s-1




Question 25 to 27.

Write the answers in the space provided.

20. The table shows the results for two experiments.

Experiment

Reactants

Time taken to collect 60 cm3 of H2(s)

1

1.0 g of magnesium ribbon and 50 cm3 of 1.0 moldm-3 sulphuric acid

30

2

1.0 g of magnesium powder and 50 cm3 of 1.0 moldm-3 sulphuric acid

10

Based on the results, state the relationship between the sizes of solid particles with the rate of reaction.

………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

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

21. The figure shows the progress of a chemical reaction.

Time(s)

0

5

10

15

20

Progress of reaction

particle of

reactant.

particle of

product.

Based on the figure, describe what happens to the amount of reactant and the amount of product as the chemical reaction progresses.

……………………………………………………………...…………………………………………………………............................................................................................................

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

Listen carefully to the text read by the teacher. Answer the question that follows.

22. Which of the followings are the reasons for the use of catalysts in industrial processes?

I. To reduce the cost of production.

II. Enables the processes to be completed in a shorter time.

III. Enables the processes to be carried out at a higher pressure.

IV. Enables the processes to be carried out at a higher temperature.

A I and II only

B I and IV only

C II and III only

D III and IV only

Listen carefully to the text read by the teacher. Answer the question that follows.

23. The use of a catalyst can increase the rate of a reaction, this is because

A a catalyst reduces the activation energy.

B a catalyst increases the activation energy.

C a catalyst reduces the number of collision.

D a catalyst increases the number of collision.


Listen carefully to the text read by the teacher. Answer questions 30 and 31.

24 What is the gas produced when hydrogen peroxide decomposes?

A Oxygen

B Hydrogen

C Carbon dioxide

D Nitrogen dioxide

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

A To increase the volume of oxygen gas.

B To decrease the volume of oxygen gas.

C To change the chemical properties of hydrogen peroxide.

D To increase the rate of decomposition of hydrogen peroxide