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In an experiment to electroplate a copper spoon with silver, a current of 0.5A was passed for 18 minutes. Calculate the amount of silver deposited...
(Solved)
In an experiment to electroplate a copper spoon with silver, a current of 0.5A was passed for 18 minutes. Calculate the amount of silver deposited on the spoon ( IF =96500 coulombs,Ag=108)
Date posted:
May 20, 2019
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Answers (1)
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Write one structural formulae of
(i) Methanol.
(ii) Methanoic acid.
(b) Write the equation for the reaction between methanoic acid and sodium hydroxide
(c) Name the product formed when...
(Solved)
Write one structural formulae of
(i) Methanol.
(ii) Methanoic acid.
(b) Write the equation for the reaction between methanoic acid and sodium hydroxide
(c) Name the product formed when methanol reacts with methanoic acid.
(d) State one condition necessary for the reaction in (c) to take place
Date posted:
May 20, 2019
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Answers (1)
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Study the flow chart below and answer the questions that follow (a) Identify W and P....
(Solved)
Study the flow chart below and answer the questions that follow
(a) Identify W and P.
(b) What name is given to the type of halogenation reaction in step 2.
Date posted:
May 20, 2019
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Answers (1)
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The table below gives information on four elements represented by K L M & N. Study it and answer the questions that follow. The letters...
(Solved)
The table below gives information on four elements represented by K L M & N. Study it and answer the questions that follow. The letters do not represent the actual symbols of the elements.
Which two elements have similar chemical properties? Explain
Date posted:
May 20, 2019
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Answers (1)
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Study the diagram below and answer the questions that follow. When some hydrogen chloride gas is allowed into water....
(Solved)
Study the diagram below and answer the questions that follow.
When some hydrogen chloride gas is allowed into water and the mixture stirred, the bulb lights and gasses X and Y are formed.
(a) Name
(i) Gas X
(ii) Gas Y
(b) Explain why the bulb does not light before the chloride gas is let into the water
Date posted:
May 20, 2019
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Answers (1)
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The structure of ammonium ion is shown below. Name the type of bond represented in the diagram by N-----> H
(Solved)
The structure of ammonium ion is shown below
Name the type of bond represented in the diagram by N-----> H
Date posted:
May 20, 2019
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Answers (1)
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Give a reason why ammonia gas is highly soluble in water.
(Solved)
Give a reason why ammonia gas is highly soluble in water.
Date posted:
May 20, 2019
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Answers (1)
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Define the following terms
(a) Isotopes
(b) Mass number
(c) Isobars
(Solved)
Define the following terms
(a) Isotopes
(b) Mass number
(c) Isobars
Date posted:
May 20, 2019
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Answers (1)
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Draw reaction cycles for the cases shown below.
(Solved)
Draw reaction cycles for the cases shown below.
Date posted:
May 20, 2019
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Answers (1)
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0.1mole of sodium chloride was dissolved in 100cm3 of water. Calculate the
concentration of this aqueous solution in grams per dm3 (Na=23, Cl=35.5).
(Solved)
0.1mole of sodium chloride was dissolved in 100cm3 of water. Calculate the
concentration of this aqueous solution in grams per dm3 (Na=23, Cl=35.5).
Date posted:
May 20, 2019
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Answers (1)
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Study the scheme given below and answer the questions that follow (a) Name the reagents used in step I,II,III,IV,V
(Solved)
Study the scheme given below and answer the questions that follow;
a) Name the reagents used in step I,II,III,IV,V:
b) Identify substances L,P,Q,R,K and N:
Date posted:
May 20, 2019
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Answers (1)
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Bromine reacts with hydrogen to form hydrogen bromide gas as shown below:
(i) Determine the molar heat of the above reaction.
(ii) Write the equation for...
(Solved)
Bromine reacts with hydrogen to form hydrogen bromide gas as shown below:
(i) Determine the molar heat of the above reaction.
(ii) Write the equation for the above case that show the molar heat of formation of
hydrogen bromide gas.
Date posted:
May 20, 2019
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Answers (1)
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A mass of 56g a saturated solution of salt X at 250C yield 14g of the solid when
evaporated to dryness. What is the solubility of...
(Solved)
A mass of 56g a saturated solution of salt X at 250C yield 14g of the solid when
evaporated to dryness. What is the solubility of the salt at 250C.
Date posted:
May 20, 2019
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Answers (1)
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A natural element represented by letter Y has two types of atoms. The composition
of the particles is as summarized below:
(Solved)
A natural element represented by letter Y has two types of atoms. The composition
of the particles is as summarized below:
(a) Complete the missing number.
(b) What is the name assigned to these two types of atoms?
(c) Which atom has the least percentage of abundance?
(d) Calculate the relative atomic mass of Y.
(e) Explain what is made by nuclear particles giving examples where possible.
Date posted:
May 20, 2019
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Answers (1)
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The extraction of aluminium from its ore takes place in two stages, purification stage
and electrolysis stage. The diagram below shows the set up for the...
(Solved)
The extraction of aluminium from its ore takes place in two stages, purification stage
and electrolysis stage. The diagram below shows the set up for the electrolysis stage.
(a) Name the ore from which aluminium is extracted.
(b) Name one impurity which is removed at purification stage.
(c) Label on the diagram each of the following:
Anode
Cathode
Region containing the electrolyte
(d) The melting point of aluminium oxide is 20540C but electrolysis is done between 8000C -
9000C.
(i) Why is the electrolysis not carried out at 20540C.?
(ii) What is done to lower the temperature of the electrolysis cell to 8000C - 9000C?
(iii) The aluminium which is produced is tapped off as liquid. What does this imply
about its melting point?
(e) A typical electrolysis cell uses a current of 40000 ampheres. Calculate the mass (in kilograms) of aluminium produced in one hour.
Date posted:
May 20, 2019
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Answers (1)
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Study the diagram below and answer the questions that follow. When some hydrogen gas is allowed into the water....
(Solved)
Study the diagram below and answer the questions that follow.
When some hydrogen gas is allowed into the water and the mixture stirred the bulb lights up
and gases X and Y are formed.
a) Name gas X
gas Y
(b) Write the chemical equations of how each of the gases is formed.
Gas X
Gas Y
(c) State any two uses of gas X.
(d) Explain why the bulb does not light before the hydrogen chloride gas is let into water.
Date posted:
May 20, 2019
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Answers (1)
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The table below gives information on four elements by letters A, B, C and D. Study it
and answer the questions that follow. The letters do...
(Solved)
The table below gives information on four elements by letters A, B, C and D. Study it
and answer the questions that follow. The letters do not represent the actual
symbols of the elements.
(a) Which two elements have two similar chemical properties? Explain.
(b) What is the most likely formula of the oxide of B?
(c) Which element is a non-metal?
(d) Which one of the elements is the strongest.
(i) Reducing agent?
(ii) Oxidising agent?
(e) Explain why ionic radius of D is less than that of C.
(f) Explain why the ionic radius of B is bigger than its atomic radius.
(g) Give the chemical family to which the element.
(i) A and D belong
(ii) B belong
(iii) C belong
(h) State any two uses of element B.
Date posted:
May 20, 2019
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Answers (1)
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The diagram below represents an incomplete paper chromatogram of pure dyes X, Y, Z and
mixture W.
(Solved)
The diagram below represents an incomplete paper chromatogram of pure dyes X, Y, Z and
mixture W.
Mixture W contains dyes Y and Z only. Complete the chromatogram to show how mixture
W separates.
Date posted:
May 20, 2019
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Answers (1)
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The flow chart below outlines some of the process involved during extraction of copper.
(Solved)
The flow chart below outlines some of the process involved during extraction of copper.
a) (i) Write the formula of copper pyrite.
(ii) Name liquid T
(iii) Write equations for the reactions taking place in the 2nd roasting furnace.
(iv) Identify substance B and write equation for the reaction that take place in the smelting furnace.
(v) State the purpose of substance F.
Date posted:
May 20, 2019
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Answers (1)
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The atomic number of sulphur is 16. Write the electron arrangement of sulphur in the
following:
(Solved)
The atomic number of sulphur is 16. Write the electron arrangement of sulphur in the
following:
Date posted:
May 17, 2019
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Answers (1)