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Chemical kinematics, equilibrium and energetics questions

Chemical kinematics, equilibrium and energetics questions | form three Chemistry

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# Question
1

In the graph below, curve 1 was obtained from the decomposition of 100 cm3 of 1.0M hydrogen peroxide solution catalysed by manganese (IV) oxide, 2H_{2}O_2 ightarrow 2H_{2}O+O_2.

Chemistry Chemical-kinematics- equilibrium-and-energetics

Which alteration/change to the original experimental conditions would produce curve 2?
A Lowering the temperature
B Using less manganese IV oxide
C Increasing the temperature
D Adding some 0.1 M H_{2}O_2
E Using a different catalyst.


Multiple choices
2

Two experiments were carried out using the same mass of magnesium ribbon and the same volume of acids of the same concentration. The acids were 1M hydrochloric acid and 1M ethanoic acid. The results were as shown in the following figure:

Chemical kinematics, equilibrium and energetics form three chemistry questions

(a) If the experiments were conducted within the same time, is there a difference in volumes of hydrogen gas collected at the same room temperature and pressure? Give reasons for your answer.
(b) When same mass, volume and concentration of powdered magnesium and ethanoic acid are allowed to react, new graph is formed. Giving reason (s), suggest the position of that graph whether will be above, between or below graphs A and B.


Short answers
3

A student attempted to prepare hydrogen gas by reacting zinc metal with dilute sulphuric acid. In this experiment zinc metal granules of about 0.5 cm diameter and 0.20 moles of acid were used. The rate of formation of hydrogen gas was found to be slow.
(a) Explain three ways in which the rate of formation of hydrogen gas could be increased.
(b) If the student wanted 36 cm 3 of hydrogen gas at s.t.p, what amount of the acid would be required.


Short answers
4

State and describe the type of reaction in the following chemical equations:

  1. Fe_{(s)} + CuSO_{4(aq)} ightarrow FeSO_{4(aq) }+ Cu_{(s)}.
  2. Na_{2}SO_{4(aq) }+ BaCl_{2(aq)} ightarrow BaSO_{4(s)} + 2NaCl_{(aq)}.

Short answers
5

In the following equilibrium equation, 2SO_{2(g)} + O_{2(g)} ightleftharpoons 2SO_{3(g)} the forward reaction is exothermic. Which change would increase the production of sulphur trioxide at equilibrium?

  1. Increasing temperature.
  2. Decreasing temperature.
  3. Decreasing sulphur trioxide concentration
  4. Decreasing pressure
  5. Adding a catalyst.

Multiple choices
6

The following equation shows the reaction between hydrogen and iodine gas to form hydrogen iodide gas,H_{2(g)} + I_{2(g)} ightleftharpoons 2HI_{(g)} ; Delta H = -800kJ/mol. Giving a reason, explain what would happen to the position of equilibrium if
(i) temperature is lowered.
(ii) hydrogen iodide gas is pumped into the system.


Short answers