KCSE CHEMISTRY QUESTIONS AND ANSWERS PER TOPIC
ANSWERS
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ANSWERS
(a) Temperature and pressure are directly proportional (l) IR words towards that of real
(b) With increase in temperature, the gas particles gain more Kinetic energy They move faster and collide with the walls of the container more frequently hence increasing pressure.
For each of the following reactions, state the observation and write the formula of the
Compound responsible for the observation: a) Bromine water is added to aqueous potassium iodide; b) Excess aqueous ammonia is added to copper (II) hydroxide (precipitate).
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(a) SiH4 it has a higher boiling point
(b) No hydrogen bonding in CH4 and SiH4 while the hydrogen bond in H2O is stronger than that in H2S
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(a) Pale green solution turns yellow
(b) Sodium hydroxide Potassium hydroxide (c) Water
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Give the name of the product formed when magnesium reacts with phosphorus.
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(a) Chemical change
(b) Physical change (c) Chemical change
The figure below represents the set up that was used to crack an alkane.
a) What was the purpose of the sand?
b) After some time, a colourless gas G collected in the test-tube. Describe a chemical test and the observations that would be made in ordered to identify the class of compounds to which gas G belongs.
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(a) Catalyst or words to that effect
(b) Add bromine water or acidified potassium magnate (VII) if they decolorize then gas is either an alkene or an alkynes
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What is the oxidation number of chlorine in CO4
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The column below was used do soften hard water
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A hydrocarbon slowly decolorizes bromine gas in the presence of sunlight but does not decolourise acidified potassium permanganate
Name and draw the structural formula of the fourth member of the series to which the hydrocarbon belongs.
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The table below gives the energy required to remove the outermost electron for some group I elements
Arrange the elements in order of their reactivity starting with the most reactive
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The diagram below shows the physical state of matter. Study it and answer the questions that follow
Identify the processes R, V, w and U
(c) Name one substance which can undergo the process represented by S and T.
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A beekeeper found that when stung by a bee, application of a little solution of hydrogen carbonate helped to relieve the irritation from the affected area. Explain.
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A student used the set up shown in the diagram below in order to study the reactions of some metals with steam. The experiment was carried out for ten minutes
a) What observation would be made if gas F is ignited?
b) When the experiment was repeated using iron powder instead of magnesium ribbon very little gas F was obtained. i) Give a reason for this observation ii) What change in the conditions of the experiment should the student have made in order to increase the volume of gas F Produced?
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(a) The gas burns with a blue flame
(b) (i) The iron isles reactive than magnesium (ii) Heat the iron powder
a) Draw and name the structure of the compound formed when one mole of ethyne reacts with one mole of hydrogen bromide.
b) Draw the structures of the alkynes whose molecular formula is C4H6
The standard reduction potentials of two half –cells are:
Ag+(aq) + e → AG(s) ; E = 0.80V 2H2O (l) + 2e → H2 (g) + 2OH (aq); E1 = 0.83V Draw a labelled diagram of an electro chemical cell that can be constructed using the two half –cells
Starting with 50 cm3 of 2.8M sodium hydroxide, describe how a sample of pure sodium sulphate crystals can be prepared.
Hydrogen and oxygen can be obtained by electrolysis of acidified water.
Using equations for the reactions at the electrodes, explain why the volume of hydrogen obtained is twice that of oxygen. ​Related Chemistry Questions and Answers on Electrochemistry Form 4 Level
a) what is meant by molar heat of solution?
b) the lattice energy of sodium bromide and hydration energies of sodium and bromide ions are: 733,406 and 335 kJmol -1 respectively. i) Complete the energy cycle diagram below by inserting the values of ΔH1, ΔH2, and ΔH3
ii) Determine the molar heat of solution of solid sodium bromide.
Using dots (.) and crosses (x) , show bonding in:
a) The compound formed when nitrogen reacts with fluorine (Atomic numbers F=9, N=7); b) Sodium oxide.(Atomic numbers Na= 11, 0 = 8) |
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