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The figure below shows the motion of a ticker tape through a ticker-timer whose frequency is 100Hz.
Determine:
I. Velocity at AB and PQ
II. Acceleration of the tape.
Date posted:
March 25, 2019
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Why is it better to use indicators rather than the sense of taste when testing for acids and alkalis?
Date posted:
March 25, 2019
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Explain briefly the following observations about a sample of hard water (a) when boiled it formed some white precipitate (b) even after boiling the water formed scum with soap (c) Sodium Carbonate made the water completely soft.
Date posted:
March 25, 2019
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Name the materials used to prepare soaps and soapless detergents.
Date posted:
March 25, 2019
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In areas of the world where a plane is unable to land free fall airdrops can be used to deliver supplies. A plane
i) Sketch the path followed by the falling load.
ii) Find the horizontal distance of the load from the drop zone to where it landed.travelling at a speed of 90m/s and a height of 100m releases a load of supplies.
Date posted:
March 25, 2019
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In an experiment, dry hydrogen chloride gas was passed through heated Zinc turnings as shown in the diagram below. The gas produced was then passed through heated Lead II Oxide.
(i) What is the function of the water in the flask?
(ii) Write equations for the reactions that took place in the tubes.
(iii) How would the total mass of tube V and its contents compare before and after the experiment? Explain.
Date posted:
March 25, 2019
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In opening a door, the moment exerted about the hinges was 15Nm. If the pushing force was 25N and perpendicular to the door, what is the distance of the force from the hinges?
Date posted:
March 25, 2019
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Paper chromatography of a plant extract gave the following results.
Which Solvent is the most suitable for purifying the extract? Explain.
Date posted:
March 25, 2019
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Figure below shows a simple barometer.
a) What is the region A?
b) What keeps the mercury in the tube?
c) What is the value of the atmospheric pressure being shown by the barometer?
d) What would happen to the reading if the barometer were taken up a high mountain.
e) Give a reason for (d) above.
Date posted:
March 25, 2019
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The diagram below shows a set up used by a student to show variation of pressure in a liquid. Use it to answer the question that follow.
State and explain the effect on the height, h, when the thistle funnel is moved upwards towards the surface of the liquids.
Date posted:
March 25, 2019
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Carbon dioxide doesn’t support combustion, yet burning of magnesium ribbon introduced in jar of carbon dioxide continues to burn. Explain this.
Date posted:
March 25, 2019
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A uniform half metre rule is pivoted at the 15cm mark and it balances when a mass of 40g is hung from the 2cm mark.Calculate the mass of the rule.
Date posted:
March 25, 2019
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Describe an experiment to investigate the “active part of air”.
Date posted:
March 25, 2019
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The spring is fitted with a scale pan as shown in the figure below and the pointer points to the 30cm mark on the scale. When some sand is placed in the pan the pointer points to 15cm mark.
When a 20g mass is placed on top of the sand the pointer points to 5.0cm mark.
a) What extension is produced by the sand?
b) What extension is produced by the 20g mass?
c) What is the mass of the sand?
Date posted:
March 25, 2019
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When a particular substance at a certain temperature is heated, it expands. When the same substance at the same temperature is cooled, it also expands.
a) What is the substance?
b) What is the temperature?
Date posted:
March 25, 2019
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In the evening the inside of green houses may be seen to have water droplets on them. Why does this happen?
Date posted:
March 25, 2019
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The diagram below shows apparatus used to observe the behaviour of smoke particle in air.
i) Why are smoke particles suitable for use in this experiment.
ii) What does the experiment tell you about the behaviour of the air molecules in the cell?
iii) What difference if any would be seen in the motion of the smoke particles if a weaker light was used.
Date posted:
March 25, 2019
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Briefly explain how ice-cream vendors use solid carbon dioxide (dry ice) to keep the ice-cream frozen.
Date posted:
March 25, 2019
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The following are some of the methods used to collect gases. With reasons state which method is suitable for each of the following gases, Ammonia, carbon dioxide, oxygen.
Date posted:
March 25, 2019
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The figure below shows a soft iron core placed between poles of two magnets. Copy the diagram and sketch the magnetic field pattern
Date posted:
March 25, 2019
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The figure below shows a soft iron ring placed between the poles of magnet. Copy the diagram and sketch the magnetic field pattern
Date posted:
March 25, 2019
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Where in Kenya is Crystallization method used? State what happens briefly.
Date posted:
March 25, 2019
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When fine chalk is suspended in water and viewed through a microscope the chalk particles appear to move in a random fashion. This motion is a result of?
Date posted:
March 25, 2019
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Briefly discuss the methods of Showing Direction.
Date posted:
March 25, 2019
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Against each mixture write down suitable methods of separation.
(a) Coloured extracts of grass dissolved in ethanol.
(b) Kerosine from Crude oil.
(c) Paraffin from water.
(d) Iron filings from Sulphur powder.
(e) Ammonium chloride from Sodium chloride.
(f) Seawater, to obtain salt.
(g) Blue Copper Sulphate crystals from aqueous copper sulphate.
Date posted:
March 25, 2019
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Why is fractional distillation suitable for separating crude oil constituents?
Date posted:
March 25, 2019
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With an aid of a diagram discuss Lava Plains and Plateaus.
Date posted:
March 25, 2019
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Explain the formation of a Volcanic Plug.
Date posted:
March 25, 2019
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Explain Plug Dome/volcano/Spine and give its characteristics.
Date posted:
March 25, 2019
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With aid of diagrams,explain the types of Volcanoes.
Date posted:
March 25, 2019