(i) River water contains Ca and /Mg2+ which react with soap to form scum
(ii) Advantage
Forms lather quickly with water
Disadvantage
It’s non-biodegradable therefore causes environment pollution e.g. froth in sewage plants.
sharon kalunda answered the question on March 29, 2019 at 13:46
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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. Answers (1)
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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. Answers (1)
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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. Answers (1)
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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. Answers (1)
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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. Answers (1)
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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. Answers (1)
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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. Answers (1)
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An organic compound with the formula C4H10O reacts with potassium metal to give hydrogen gas and a white solid.
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(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. Answers (1)
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Date posted: March 29, 2019. Answers (1)
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Date posted: March 29, 2019. Answers (1)
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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. Answers (1)
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(C=12;O=16)(Solved)
An oxide of carbon contains 42.8% by mass of carbon and has R.M.M. of 28. What is its molecular formula?
(C=12;O=16)
Date posted: March 29, 2019. Answers (1)
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Calculate the enthalpy change of the reaction.
Date posted: March 29, 2019. Answers (1)
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(i) How much salt Y would saturate 190g of...(Solved)
The solubility of salt Y at 600 is 40g/100g of water and 48g/100g of water at 1000C.
(i) How much salt Y would saturate 190g of water at 1000C.
(ii) 150g of saturated solution of Y at 1000C is cooled to 600C. Calculate the mass of Y that crystallizes out.
Date posted: March 29, 2019. Answers (1)
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Study the information in the table below and answer the questions that follow.
(a) Explain why the ionic radius of K+ is greater than that of Na+
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Date posted: March 29, 2019. Answers (1)
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Four solutions of pH 7, 2, 8.5 and 13 respectively were each reacted with calcium turnings. Identify two solutions in which hydrogen gas would be produced. Explain each case.
Date posted: March 29, 2019. Answers (1)
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Describe how you would prepare a dry sample of zinc carbonate in the laboratory starting with zinc chloride solid.
Date posted: March 29, 2019. Answers (1)
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Date posted: March 29, 2019. Answers (1)
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The diagrams below represent a list of apparatus which are commonly used in a chemistry laboratory:-
(a) Give the correct order of the apparatus, using the letters only, show the correct arrangement that can be used to prepare and investigate the nature of PH of a sample of onion solution.
(b) Name one chemical substance and apparatus that is needed in the experiment.
Date posted: March 29, 2019. Answers (1)
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Use the information in the table below to determine the relative atomic mass of copper.
Date posted: March 29, 2019. Answers (1)