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The flow chart below illustrates the industrial extraction of lead metal. Study it and answer the questions that follow.
(i) Name the ore that is commonly used in this process.
(ii) Explain what takes place in the roasting furnace.
(iii) Identify gas P.
Date posted:
May 16, 2017
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The flow chart below shows a sequence of reactions starting with iron. Study it and answer the questions that follow.
(i) Name the reagent and state the condition for the reaction in step I.
(ii) Give the name of the following: (I). Solid S (II) Solid V (III) Solid T
(iii) Give reasons for the colour change in step 2.
Date posted:
May 16, 2017
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The diagram below shows the extraction of sodium metal using the Downs cell. Study it and answer the questions that follow:
(i) Explain why in this process the sodium chloride is mixed with calcium chloride.
(ii) Why is the anode made of graphite and not steel?
(iii) State the properties of sodium metal that makes it possible for it to be collected as shown in the diagram.
iv) What is the function of the steel guaze cylinder?
v)Why is the anode made of graphite in this case instead of steel which is a better conductor of electricity?
vi)Give reasons why large quantities of electricity is required for this process
Date posted:
May 16, 2017
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Outline the composition of the Cabinet in Kenya
Date posted:
May 16, 2017
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State the powers and functions of the president in Kenya
Date posted:
May 16, 2017
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Discuss the qualifications for one to be elected as a president in Kenya.
Date posted:
May 16, 2017
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State the demerits of parliamentary supremacy
Date posted:
May 16, 2017
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Describe merits of parliamentary supremacy.
Date posted:
May 16, 2017
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What are the requirements or qualifications for one to qualify as a candidate in the elections to the county assembly Kenya?
Date posted:
May 16, 2017
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What is the composition of the County Assembly in Kenya?
Date posted:
May 16, 2017
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What are the functions of the Senate in Kenya?
Date posted:
May 16, 2017
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State functions of the National Assembly.
Date posted:
May 16, 2017
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Discuss the functions of parliament in Kenya
Date posted:
May 16, 2017
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Figure 10 shows a trolley of weight 20 N pulled by a force of 4 N from the bottom to the top of an inclined plane at a uniform speed.
(i) State the value of the force acting downwards along the inclined plane.
(ii) Explain how the value in part (a)(i) is obtained.
Date posted:
May 16, 2017
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Figure 10 shows a pulley system used to raise a load by applying an effort of 500 N
State the:
(i) Velocity ratio of the system.
(ii) Purpose of pulley 2.
(iii) Given that the machine has an efficiency of 80%, determine the maximum load that can be raised.
Date posted:
May 16, 2017
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Figure 16 shows a screw jack whose screw has a pitch of 1 mm, and has a handle of 25 cm long.
Determine the velocity ratio of the jack.
Date posted:
May 16, 2017
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Figure 7 shows a mass of 30 kg being pulled from point P to point Q, with a force of 200 N parallel to an inclined plane. The distance between P and Q is 22.5 m. In being moved from P and Q the mass is raised through a vertical height of 7.5 m.
Determine the work done:
(I) By the force;
(II) On the mass;
(III) To overcome friction.
Date posted:
May 16, 2017
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Figure 5 shows two pulley systems being used to raise different loads. The pulleys are identical.
State one reason why system B may have a higher efficiency than system A.
Date posted:
May 16, 2017
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Two identical spherical steel balls are released from the top of two tall jars containing liquids L1 and L2 respectively. Figure 3 shows the velocity-time graph of the motion of the balls.
Explain the nature of the curves and state why they are different.
Date posted:
May 16, 2017
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Figure 9 shows graph of velocity against time for a ball bearing released at the surface of viscous liquid.
Explain the motion of the ball bearing for parts.
(i) OA
(ii) AB
Date posted:
May 15, 2017
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Figure 9 shows a velocity-time graph for the motion of a certain body.
Describe the motion of the body in the region;
(i) OA; (ii) AB; (iii) BC;
Date posted:
May 15, 2017
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Figure 5 shows air flowing through a pipe of different cross-sectional areas. Two pipes A and B are dipped into water.
Explain the cause of the difference in the levels of water in the pipes A and B.
Date posted:
May 15, 2017
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Figure 6 shows two inflated balloons hanging vertically on light threads.
When a stream of air is blown in the space between the balloons, they are observed to move towards each other. Explain this observation
Date posted:
May 15, 2017
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The extraction of aluminium from its ore takes place in two stages, purification stage and electrolysis stage. The diagram below shows the set up for the electrolysis stage.
i) Name the ore from which aluminium extracted
ii) Name one impurity which is removed at the purification stage
Date posted:
May 15, 2017
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The flow chart below outlines some of the processes involved during extraction of copper from copper pyrites. Study it and answer the questions that follow.
i) Name gas K
ii) Write the formula of the cation present in slag M
iii) Identify gas P
vi) What name is given to the reaction that takes place in chamber N?
Date posted:
May 15, 2017
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The diagram below represents a dry cell. Use it to answer the questions that follow.
i) Which of the letters represent:
I) Carbon electrode?
II) The electrolyte?
ii) One of the substances used in a dry cell is manganese (IV) oxide. State two roles of manganese (IV) oxide in the dry cell.
Date posted:
May 15, 2017
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The set up below was used to investigate the products formed at the electrodes during electrolysis of aqueous magnesium sulphate using inert electrodes. Use it to answer the questions that follow.
i) During the electrolysis hydrogen gas was formed at electrode Y. Identify the anode. Give a reason for your answer.
ii) Why is the concentration of magnesium sulphate expected to increase during electrolysis?
iii) What will be observed if red and blue litmus papers were dipped into the solution after electrolysis?
Date posted:
May 15, 2017
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The apparatus shown in the diagram below were used to investigate the products formed when concentrated sodium chloride was electrolyzed using inert electrodes
a) Write the equation for the reaction that takes place at electrode A.
b) If the concentrated sodium chloride was replaced with dilute sodium chloride, what product would be formed at electrode A? Explain.
Date posted:
May 15, 2017
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The set-up below (Figure 2) was used to electrolyse a bromide of metal D, DBr2.
a) Write the equation for the reactions at the I. Cathode II. Anode
b) The electrodes used in the experiment were made of carbon and metal D. Which of the two electrodes was used as the anode? Give a reason
c) Give a reason why this experiment is carried out in a fume cupboard.
Date posted:
May 15, 2017
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The diagram below represents an experiment that was set up to investigate movement of ions during electrolysis.
When the circuit was completed, it was noticed that a blue colour spread towards the right.
a) Explain this observation.
b) Write the equation for the reaction that occurred at the anode.
Date posted:
May 15, 2017