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Explain four precautions that can be taken to prevent typhoid being transmitted
Date posted:
October 1, 2019
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In temperate countries, salt is sprayed on roads to defrost and clear roads but the long term effect on this practice is costly to motorist.
(a) Explain the role of salt in defrosting the ice.
(b) Explain why the long term effect is costing to motorist.
Date posted:
October 1, 2019
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Sickle – cell anaemia is a hereditary disease due to mutation of gene for normal haemoglobin to gene that causes sickle cell anaemia. What are the possible phenotype offspring of a man and a woman both heterozygous.
Date posted:
October 1, 2019
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Study the table below.
(a) Which elements belong to the same period of the periodic table?
(b) What is the formula of the compound formed by L and N.?
(c) Compare the atomic and ionic radii of element L.
Date posted:
October 1, 2019
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A student set-up the apparatus below in order to determine the percentage by volume of oxygen in air.
a) Why did water rise when the reaction had stopped?
b) The student wrote the expression for the percentage by volume of oxygen in air as
Why was the volume of oxygen calculated using the above expression incorrect?
c) What should have been done after the reaction had stopped in order to get a correct volume.
Date posted:
October 1, 2019
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Pollen from a red – flowered plant A was used to pollinate white flowered plant B, the seeds from which produced 157 red-flowered plants. When a red flowered plant C was pollinated by a white-flowered plant D, the resultant seeds gave rise to 84 red-flowered plants: and 91 white flowered plants. Assuming that plants A, B, C, and D were all of the same species and that flower colour in that species is controlled by a single pair of genes.
Using R for dominant gene and r for recessive gene, write down the genotypes of the following.
i)Plant A
ii)Plant B
iii)Progeny of A x B cross
iv)Plant C
v)Plant D
vi)Red flowered progeny of C x D cross.
Date posted:
October 1, 2019
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State two symptoms of gout disease in man.
Date posted:
October 1, 2019
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Distinguish between gaseous exchange and respiration
Date posted:
October 1, 2019
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Two solutions J and K were tested with blue litmus papers and methyl orange indicator.
Blue litmus remained blue in both solutions. Methyl orange remained orange in K but turned yellow in J.
(a) What is the nature of substance J? Explain.
(b) Give an example of a substance that K is likely to be.
Date posted:
October 1, 2019
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Nocturnal animals such as the owl are capable of seeing fairly well at night. What two adaptations have made this possible.
Date posted:
October 1, 2019
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A scientist has discovered a rare disease that attacks the respiratory system in insects. Name two parts of an insect, which are most likely to be damaged by the disease.
Date posted:
October 1, 2019
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State with reasons whether the changes below are physical or chemical.
Date posted:
October 1, 2019
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Under what condition would a plant lose more water than its absorbing from the soil.
Date posted:
October 1, 2019
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Explain how Antiduretic hormone regulates osmotic potential in the body
Date posted:
October 1, 2019
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Distinguish between Secretion and excretion.
Date posted:
October 1, 2019
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Describe how the following reagents can be used to prepare copper (II) hydroxide, solid copper (II) sulphate, solid sodium hydroxide and distilled water.
Date posted:
October 1, 2019
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Complete the table below for the characteristics of the sub atomic particles.
Date posted:
October 1, 2019
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Explain the disadvantages of using acarides in tick control
Date posted:
October 1, 2019
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Name two methods that would be used to measure growth in plants.
Date posted:
October 1, 2019
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A frustrum whose vertical height is 4cm is formed by cutting the top of a cone parallel to the base if the two radii of the frustrum are 6cm and 8cm respectively, determine the height of the original cone.
Date posted:
October 1, 2019
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State two precautions you would observe when preparing a bacteria culture in the laboratory.
Date posted:
October 1, 2019
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Using a punnet square, explain why the view that “some women have a tendency to giving birth to girl or boy babies only” has no scientific foundation.
Date posted:
October 1, 2019
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The flow chart below illustrates two industrial processes, Haber process and the Contact process:
(a) (i) Give the name of the process by which air is seperated into oxygen and nitrogen
(i) Apart from oxygen and nitrogen gases produced from process (a)(i) name one other gas produced
(b) Name the substances represented by the letters A, B, C and D
(c) Name the catalysts used in:
(i) Haber Process
(ii) Contact Process
(d) Explain the role of the catalysts in both the Haber and the Contact processes
(e) Write a chemical equation for the formation of compound B
(f) Calculate the percentage by mass of the nitrogen present in compound D
(g) Give one major use of compound D
Date posted:
October 1, 2019
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In maize, yellow colour is dominant over White colour. Using letter W to denote gene for maize colour, show how one would establish whether a given sample of yellow maize is pure or a hybrid.
Date posted:
October 1, 2019
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Study the set-up below and answer the questions that follow.
a) (i) Name Gas X
(ii) State the effect of releasing gas X to the environment
b) Write down equations for the reactions taking place in;
(i) Tube I
(ii) Tube II
(iii) Flask
c) State the observation made in tube III
d) Write down an equation for the reaction which could be used to generate Carbon (IV) Oxide for the above set up
(e) Name the reagents used to generate gas X in the laboratory
(f) Complete the diagram above to show how excess gas X can be collected
Date posted:
October 1, 2019
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The grid below shows a part of the periodic table. The letters do not represent the actual symbols. Use it to answer the questions that follow:-
a) How do the atomic radius of element
(i) X and M compare. Explain.
(ii) U and Q. Explain
b) Which letter represent the most reactive metal. Explain.
Date posted:
October 1, 2019
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To determine the relationship between angular velocity w and tension T, a student used a smooth disc with a hole at the centre, a string and cylindrical object of mass m, as shown below
Describe how the student went about determining the relationship, specifying any other necessary material or instrument not shown in the diagram
Date posted:
October 1, 2019
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A bicycle wheel with radius 28cm moves with a linear velocity of 8m/s, determine
(i) the angular velocity of the wheel
(ii) the centripetal acceleration of a point on the rim of the wheel
Date posted:
October 1, 2019
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Explain the functions of complementary metal-oxide semiconductor (CMOS)
Date posted:
October 1, 2019
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The number of protons, neutrons and electrons in atoms A to F are given in the table below the letters do not represent the actual symbol of the elements:-
Choose from the table the letters that represent:
(i) An atom of a metal
(ii) A neutral atom of a non-metal
(iii) An atom of a noble gas
(iv) A pair of isotopes
(v) A cation
(vi) Anion
Date posted:
October 1, 2019