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57.2g of hydrated sodium carbonate (Na2CO3.XH2O) were dissolved in water and the solution made to one litre. 20cm3 of 0.5M HCl recated with 25cm3 of the hydrated sodium carbonate solution. Determine the value of X. (Na = 23, C = 12, O = 16)
Date posted:
April 1, 2019
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A student tried to prepare aluminium carbonate by mixing a solution of aluminium chloride and a solution of sodium carbonate but did not succeed. Explain.
Date posted:
April 1, 2019
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Phosphorus has an atomic number of 15. State the type of bond formed when phosphorous combines with bromine.
Date posted:
April 1, 2019
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Using oxidation numbers identify the oxidizing agent in the reaction below.
Date posted:
April 1, 2019
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Would copper be suitable to prevent rusting in iron? Explain.
Date posted:
April 1, 2019
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Filtration is usually carried out in the purification of water. Which other process would be required to obtain water for drinking?
Date posted:
April 1, 2019
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a)A hydrocarbon decolourises both bromine gas and acidified potassium permanganate.Name and draw the structure of the fourth member of the series to which the hydrocarbon belongs.
b)To which homologous series does (a) above belong to.
Date posted:
April 1, 2019
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The formula given below represents a portion of a polymer.
(i) Give the name of the monomer.
(ii) State one disadvantage of continued use of the polymer.
(iii) State one use of the polymer.
Date posted:
April 1, 2019
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The table below shows the formulae of the chlorides of P, Q, R and S ( not the actual symbols )
(i) State the group to which the elements belong.
P
Q
R
S
(ii) Which of the chlorides would conduct electricity when dissolved in water . Explain.
Date posted:
April 1, 2019
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The equilibrium reaction of phenolphthalein indicator in water may be represented as follows.
State and explain the observations made when an acid is added to the equilibrium
mixture.
Date posted:
April 1, 2019
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Study the chart below and answer the questions that follow.
(i) Identify metal ion present in solution M.
(ii) Give the formula of the complex ion in
I) Solution P
II) Solution N
Date posted:
April 1, 2019
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Draw the isomers of the compound C3H7Cl and give their systematic names.
Date posted:
April 1, 2019
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What do you understand by the term isomers ?
Date posted:
April 1, 2019
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Calculate the mass of calcium carbonate that would react completely with 20cm 3 of 0.2M hydrochloric acid (Ca = 40.0, C = 12.0, O = 16.0)
Date posted:
April 1, 2019
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The following graph represents a thermochemical process
(a) What does Y represent.
(b) Is the overall reaction exothermic or endothermic. Explain your answer.
Date posted:
April 1, 2019
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Why is water not used to put off oil fires?
Date posted:
March 29, 2019
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Suppose 180cm3 of a 2.0M solution is diluted to 1.0dm3. What will be the concentration of the resulting solution.
Date posted:
March 29, 2019
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Using the following standard electrode potentials to answer the questions that follow.
Calculate the e.m.f of the following cell:
Date posted:
March 29, 2019
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The formula below represents the active ingredients in a soap and a detergent respectively.
(a)Explain why (I) is suitable for washing using water from a river.
(b) Give one advantage and one disadvantage of II.
Date posted:
March 29, 2019
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The diagram below shows the appearance of two pieces of paper placed in different parts of a non-luminous flame of a Bunsen burner and removed quickly before they caught fire.
(a) What do the experiments show about the outer region of the flame?
(b) From the above experiment, which part of the flame is better to use for heating? Give a reason
Date posted:
March 29, 2019
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The isotope decays
by Beta,-emission to a stable nuclide. The half-life of the isotope is 15 hours 2.0g of allowed to decay. Determine the mass left after 90 hours.
Date posted:
March 29, 2019
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Write the discharge equations (half equations) for the electrode reactions when molten sodium chloride is electrolyzed using graphite electrodes.
Anode
Cathode
Date posted:
March 29, 2019
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Ammonia gas was passed into water as shown below.
(a) When a red litmus paper was dropped into the resulting solution; it turned blue.Give a reason to this observation.
(b) What is the function of the funnel?
Date posted:
March 29, 2019
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The following diagram represents a set-up that can be used in the laboratory to prepare and collect a sample of chlorine gas:
a)No gas bubbles were produced in the above experiment. Explain the observation.
(b) Complete the following equation.
Cl2(g) + H2O(l)---------->
(c) Describe the bleaching property of chlorine water
Date posted:
March 29, 2019
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During purification of copper by electrolysis, 1.48g of copper were deposited when a current was passed through aqueous copper (II) sulphate for 2 ½ hours. Calculate the amount of current that was passed.(Cu = 63.5; IF = 96500C)
Date posted:
March 29, 2019
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Two experiments were carried out as follows and the volume of hydrogen gas evolved measured at intervals of 10 seconds for 100 seconds.
i) 8cm of magnesium ribbon was added to 1M HCl(aq)
(ii) 8cm of magnesium ribbon was added to 0.5M HCl(aq)
Graphs of volume of hydrogen gas evolved against time were plotted as shown below.
a) Which of the graphs was obtained for reaction (i). Explain.
(b) Explain the general shape of the graphs.
Date posted:
March 29, 2019
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An organic compound with the formula C4H10O reacts with potassium metal to give hydrogen gas and a white solid.
(a) Write structural formula of the compound.
(b) To which homologous series does the compound belong?
(c) Write the equation for the reaction between the compound and potassium metal.
Date posted:
March 29, 2019
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Give the systematic names of the following compound: CHCH=CHCH2CH3.
Date posted:
March 29, 2019
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A known volume of ozone diffuses through a small hole in 55 seconds; whereas the same amount of chlorine takes 67 seconds under the same conditions.Determine the molecular mass of ozone . (Cl=35.5; O=16)
Date posted:
March 29, 2019
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Sulphur (IV) oxide gas was bubbled into acidified potassium chromate (VI) and iron (III) sulphate solutions respectively.Explain the observations made in each case.
i) With potassium chromate (VI).
(ii) With iron (III) sulphate.
Date posted:
March 29, 2019