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Explain why molten calcium chloride conducts electricity while silicon (IV) oxide does not.
Date posted:
October 1, 2019
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A certain metabolic pathway takes the following sequence.
J ----- K ----- L ----- M ----- N
At the start of the experiment an inhibitor was added to the reactants. After the experiment it was found that there was the same concentration of J more than normal concentration of K; near absence of L, M, and N.
When L was added to the inhibitor set M and N were detected.
a)At what stage of the reaction sequence did the inhibitor have its effects?
b)Explain how the inhibitor affected the reaction.
Date posted:
October 1, 2019
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In what ways did the healer act as a counselor in the traditional African Society.
Date posted:
October 1, 2019
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Phosphorus element smoulders in air to form two oxides
(a) Name the two oxides
(b) State the nature of the solution when the above mentioned oxides are dissolved in water.
Date posted:
October 1, 2019
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The diagrams below are some common laboratory apparatus. Name each apparatus and state its use.
Date posted:
October 1, 2019
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(a) What name is given to the two types of atoms.
Date posted:
October 1, 2019
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Oxygen is obtained on large scale by the fractional distillation of air as shown on the flow chart below.
a) Explain why air is considered as a mixture
b) Identify the substance that is removed at the filtration stage
c) Explain why Carbon (IV) oxide and water are removed before liquefaction of air
d) Identify the component that is collected at -186°C
Date posted:
October 1, 2019
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Soma shairi lifuatalo kisha ujibu maswali.
Zitavuma,
Zitakoma,
Nitakwima,
Mti-mle.
Na muda nikisimama,
Nitatongoa nudhuma,
Kwa tenzi zilizo njema,
Nilisifu mti – mle.
Tazipanga tathlitha, tungo zilizo na hekima,
Za huba na thiatha, za kuburudi mitima,
Mashairi mabuthutha, musome mnaosoma.
Mti nishainukia,namea kuwa mzima,
Mizizi yadidimia, ardhini imeuma,
Nanena kitarbia, tungo zilizo adhama
Japo ni tungo za zama, mti-mle hutumia.
Zingavuma zitapusa, pepo kali zitakoma,
Dharuba kinitikisa, mti-mle huinama,
Huyumba nikaziasa, matawi yakakingama,
Gharika ikishapisa, hurudi nikawa wima,
Na tungo za takhimisa, mti-mle huzipima.
Maswali
(1) Shairi hili ni la kimapokea. Toa sababu mbili kuunga kauli hii.
(2) Taja bahari kuu ya ushairi ambayo imetumiwa na mshairi. Fafanua.
(3) Fafanua dhamira ya mshairi.
(4) Kwa kutoa mifano bainisha tamathali mbili za usemi zilizotumika katika shairi hili.
(5) Eleza jinsi mshairi ametumia idhini ya ushairi katika utungo huu.
(6) Andika ubeti wa nne kwa lugha natharia.
(7) Mshairi anamaanisha nini anaposema "zingavuma zitapusa, pepo kali zitakoma,"
(8) Eleza toni ya shairi hili.
(9) Eleza maana ya msamiati ufuatao.
i) Nitatongoa
ii) Zitapusa.
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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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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Under what condition would a plant lose more water than its absorbing from the soil.
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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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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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
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Briefly explain what happen during power on self test (POST)
Date posted:
October 1, 2019
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When zinc is heated to redness in a current of steam, hydrogen gas is obtained. Write an equation for the reaction
Date posted:
October 1, 2019
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Hydrogen burns in oxygen to form an oxide.
(i) Write an equation for the reaction
(ii) State two precautions that must be taken before the combustion begins and at the end of
the combustion.
Date posted:
October 1, 2019
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Hydrogen can be prepared by reacting zinc with dilute hydrochloric acid.
a) Write an equation for the reaction.
b) Name an appropriate drying agent for hydrogen gas.
c) Explain why copper metal cannot be used to prepare hydrogen gas.
Date posted:
October 1, 2019
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The diagram below shows two trolleys, A and B connected to each other by an elastic strip of negligible mass. The trolleys are pulled apart on a smooth plane till tension in the elastic strip is 4.0N and are then released suddenly
(a) State with reason the total momentum of the trolleys when they are just released
(b) Calculate the initial acceleration of trolley A when released
(c) The velocity of the trolley B is 0.9ms-1 just before it collides with A. Determine the velocity of A just before the collision
(d) Which trolley covers a longer distance before collision? Explain
(e) Explain why the elastic strip may not stretch to the same original length after impact
Date posted:
October 1, 2019
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Business studies are a wide subject that covers several disciplines. Outline those five disciplines.
Date posted:
October 1, 2019