The first amount of soap precipitates Ca2+(aq) and Mg2+(aq) ions and soften water.
Then additional soap dissolves oil from the fabric.
maurice.mutuku answered the question on November 1, 2019 at 11:25
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Write chemical equation to represent the effect of heat on ammonium carbonate
(Solved)
Write chemical equation to represent the effect of heat on ammonium carbonate
Date posted:
November 1, 2019
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Answers (1)
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The structure of the monomer phenyl ethene is given below:-
(Solved)
The structure of the monomer phenyl ethene is given below:-
a) Give the structure of the polymer formed when four of the monomers are added together
b) Give the name of the polymer formed in (a) above
Date posted:
November 1, 2019
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Answers (1)
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The following table shows some properties of period three elements and their chlorides. Study it and answer the questions that follow.
a)Complete the table by filling...
(Solved)
The following table shows some properties of period three elements and their chlorides. Study it and answer the questions that follow.
a)Complete the table by filling in the formula of the missing chlorides.
b)In terms of structure and bonding, explain the following observations:
i)The melting point of aluminium is higher than that of sodium.
ii)The melting point of chlorine is lower than that of sulphur.
iii)The melting point of aluminium chloride is lower than that of magnesium chloride.
c)Sodium chloride dissolves in water to form a neutral solution but aluminium chloride dissolves
to form an acidic solution. Explain this observation.
d)Generally, the first ionization energy increases across the period. Explain
e)Iron (III) oxide was found to be contaminated with magnesium chloride. Describe how a pure dry sample of iron (III) oxide can be obtained.
Date posted:
November 1, 2019
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Answers (1)
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A current of 3A was passed through fused aluminium oxide for 10minutes. Calculate the mass of Aluminium obtained at one electrode (Al = 27.0, IF...
(Solved)
A current of 3A was passed through fused aluminium oxide for 10minutes. Calculate the mass of Aluminium obtained at one electrode (Al = 27.0, IF = 96500C)
Date posted:
November 1, 2019
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Answers (1)
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When air is bubbled through pure water of pH 7.0, the pH drops to 6.0. Explain.
(Solved)
When air is bubbled through pure water of pH 7.0, the pH drops to 6.0. Explain.
Date posted:
November 1, 2019
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Answers (1)
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The sketch below shows a graph of temperature against time obtained when a gaseous substance was cooled.
Explain what happens to the gaseous substance between:
a)T and...
(Solved)
The sketch below shows a graph of temperature against time obtained when a gaseous substance was cooled.
Explain what happens to the gaseous substance between:
a)T and U
b)U and V
c)V and W
Date posted:
November 1, 2019
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Answers (1)
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The flow chart below illustrates the extraction of Zinc. Study it and answer the questions that follow:
(Solved)
The flow chart below illustrates the extraction of Zinc. Study it and answer the questions that follow:
a) Name:-
i) Gas Q
ii) Liquid R
(iii) Residues S
b) Name the sulphide ore used
c) Before the ore is roasted, it is first concentrated;
(i) Explain why it is necessary to concentrate the ore
(ii) Explain briefly the process of concentrating the ore
d) Write an equation for the reaction that takes place in the:-
(i) Roaster
(ii) Reaction chamber
(e) (i) Name one major impurity present in the sulphide ore used
(ii) Write an equation to show how the impurity in (e)(i) above is removed
f) Given that the sulphide ore contains only 45% Zinc sulphide by mass, calculate :
(i) The mass in grams of Zinc sulphide that would be obtained from 250kg of the ore.
(ii) The volume of Sulphur (IV) oxide that would be obtained from the mass of sulphide
ore at room temperature and pressure
(Zn = 65.4, S = 32.0, O= 16.0, I mole of gas occupies 24.0 liters at r.t.p)
Date posted:
November 1, 2019
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Answers (1)
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The diagram below is a flow chart for the extraction of copper. Study it and answer the questions that follow:
(Solved)
The diagram below is a flow chart for the extraction of copper. Study it and answer the questions that follow:
(a) Write the formula of the major ore of copper metal
(b) Name process II
(c) Give an equation for the reaction that occurs in stage III
(d) Explain what happens in stage IV
(e) Write half cell equations occurring at the anode and cathode in stage VII
(f) Draw a simple diagram showing the set-up that is used in electrolytic purification of copper
Date posted:
November 1, 2019
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Answers (1)
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The flow chart below shows steps used in the extraction of zinc from one of its ores.
(Solved)
The flow chart below shows steps used in the extraction of zinc from one of its ores.
(a) Name the process that is used in step 2 to concentrate the ore
(b) Write an equation for the reaction which takes place in step 3
Date posted:
November 1, 2019
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Answers (1)
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The stages shown in the following diagram can be used to extract zinc from its oxide.
Name the stage and the process taking place in it:-
(Solved)
The stages shown in the following diagram can be used to extract zinc from its oxide.
Name the stage and the process taking place in it:-
Stage 1
Stage 2
Stage 3
Date posted:
November 1, 2019
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Answers (1)
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What properties of aluminium and its alloys make it suitable for use in making aircraft parts
(Solved)
What properties of aluminium and its alloys make it suitable for use in making aircraft parts
Date posted:
November 1, 2019
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Answers (1)
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Suggest one manufacturing plant that can be set up near zinc extraction plant. Give
reasons for your answer
(Solved)
Suggest one manufacturing plant that can be set up near zinc extraction plant. Give
reasons for your answer
Date posted:
November 1, 2019
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Answers (1)
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Give one environmental hazard associated with the extraction of zinc metal
(Solved)
Give one environmental hazard associated with the extraction of zinc metal
Date posted:
November 1, 2019
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Answers (1)
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You are provided with 20.0cm3 of 2M sodium hydroxide solution. Explain how you would prepare a solution of sodium hydroxide whose concentration is 0.16M.
(Solved)
You are provided with 20.0cm3 of 2M sodium hydroxide solution. Explain how you would prepare a solution of sodium hydroxide whose concentration is 0.16M.
Date posted:
October 31, 2019
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Answers (1)
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The following diagram represents the electrolysis of dilute sodium chloride solution using inert
electrodes
(Solved)
The following diagram represents the electrolysis of dilute sodium chloride solution using inert
electrodes
Determine the electrode at which different electrolytic products would be produced if the solution is electrolysed for several hours. Explain
Date posted:
October 31, 2019
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Answers (1)
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The standard hydrogen electrode is used as the reference electrode. Some of the difficulties in using hydrogen gas as an electrode are:
(Solved)
The standard hydrogen electrode is used as the reference electrode. Some of the difficulties in using hydrogen gas as an electrode are:
- Hydrogen is a gas at 25oC
- Hydrogen does not conduct electricity
-The half-cell reaction,
is slow and takes long to reach equilibrium.
Explain how these difficulties are solved in the standard hydrogen electrode
Date posted:
October 31, 2019
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Answers (1)
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Give the chemical formula of Zinc blende
(Solved)
Give the chemical formula of Zinc blende
Date posted:
October 31, 2019
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Answers (1)
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The following is an equation for the reaction between ammonia and water
(Solved)
The following is an equation for the reaction between ammonia and water
Name the base in the backward reaction
Date posted:
October 31, 2019
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Answers (1)
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Calculate the volume at s.t.p of hydrogen evolved when 2A of electricity are passed
through dilute sulphuric acid for 2hours.
(Molar gas volume at s.t.p = 22.4dm3,...
(Solved)
Calculate the volume at s.t.p of hydrogen evolved when 2A of electricity are passed
through dilute sulphuric acid for 2hours.
(Molar gas volume at s.t.p = 22.4dm3, one Faraday= 96500coulombs)
Date posted:
October 31, 2019
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Answers (1)
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State Faradays First Law of Electrolysis
(Solved)
State Faradays First Law of Electrolysis
Date posted:
October 31, 2019
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Answers (1)