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In terms of structure and bonding explain why diamond has a high melting point while
graphite has a low melting point.
(Solved)
In terms of structure and bonding explain why diamond has a high melting point while
graphite has a low melting point.
Date posted:
May 16, 2019
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Answers (1)
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Two elements A and B have electronic configurations 2.8.3 and 2.6 respectively.
(Solved)
Two elements A and B have electronic configurations 2.8.3 and 2.6 respectively.
a) To which group and period does element B belong?
b) If the two react, what is the formula of the compound they form
Date posted:
May 16, 2019
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Answers (1)
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Lead (II) ions react with iodide ions according to the equation
(Solved)
(i) Lead (II) ions react with iodide ions according to the equation
300cm3 of 0.1M solution of iodide ions was added to a solution containing Lead (II)
ions. Calculate the mass of Lead (II) iodide formed (Pb= 207, I = 127).
(ii) Identify the colour of the product formed after the reaction above.
Date posted:
May 16, 2019
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Answers (1)
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(i) State and explain what is observed when ammonia solution is gradually added to a solution of Lead (II) nitrate until the alkali (ammonia) is...
(Solved)
(i) State and explain what is observed when ammonia solution is gradually added to a solution of Lead (II) nitrate until the alkali (ammonia) is in excess.
(ii) Write an equation for the reaction that takes place in (i) above
Date posted:
May 16, 2019
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Answers (1)
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When Lead (II) nitrate crystals is heated strongly the crystals crackle and split because
of the gas accumulating inside.
(Solved)
When Lead (II) nitrate crystals is heated strongly the crystals crackle and split because
of the gas accumulating inside.
(i) State three other observations that are made.
(ii) Write an equation for the reaction that takes place when Lead (II) nitrate is
strongly heated.
Date posted:
May 16, 2019
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Answers (1)
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(i) Describe how Lead(II) nitrate is prepared in the Laboratory starting from Lead (II) Oxide.
(ii) Write an equation for the reaction that takes place in...
(Solved)
(i) Describe how Lead(II) nitrate is prepared in the Laboratory starting from Lead (II) Oxide.
(ii) Write an equation for the reaction that takes place in (i) above
Date posted:
May 16, 2019
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Answers (1)
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The chart below shows some of the chemical needed for the production of ammonia gas, nitric
acid and ammonia sulphate in the industry.
(Solved)
The chart below shows some of the chemical needed for the production of ammonia gas, nitric
acid and ammonia sulphate in the industry.
(a) Name the chemical that should be in chambers 1,2, 4, 6, 8 and 9
b) State three conditions required to convert the chemical substance in chamber 3 to
SO3(g).
c) Write balanced equations with conditions where necessary for the reactions that
produces chemical substances in chambers:-
Date posted:
May 16, 2019
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Answers (1)
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The table below shows the atomic numbers of some elements represented by letter J to Q ( letters
not their actual symbols). Study and answer the...
(Solved)
The table below shows the atomic numbers of some elements represented by letter J to Q ( letters
not their actual symbols). Study and answer the questions that follow.
a) Write the electronic configuration of
(i) M
(ii) P2+
b) Write the formula of the compound formed when L combines with N
c) How would reactivities of element N and P with chlorine compare? Explain.
d) Element N combines with oxygen to from an oxide. Using dots (.) and crosses(x) to
represent the outermost electrons, show how the two elements combine.
e) Select the most reactive metal and non-metal and give reason for your answer.
f) State one physical and one chemical property that elements J and Q have in common
g) What name is given to the group of elements to which element M belong?
h) (i) Element K consists of two isotopes with relative abundances 75% and 25% and
mass number 35 and 37 respectively find the relative atomic mass of K.
(ii) Why is the relative atomic mass of K not a whole number?
Date posted:
May 13, 2019
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Answers (1)
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The diagram below shows a Bunsen burner when in use
(Solved)
The diagram below shows a Bunsen burner when in use
Which of the labeled parts is used for heating? Give a reason
Date posted:
May 13, 2019
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Answers (1)
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During the extraction of lead from its ores one of the main ore used is Galena
(Solved)
During the extraction of lead from its ores one of the main ore used is Galena
(i) Write an equation for the reaction in roasting furnace.
(ii) Name gas
(iii) State one use of lead metal.
Date posted:
May 13, 2019
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Answers (1)
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Describe how you would prepare crystals of sodium nitrate starting with 200cm3 of 2M
sodium hydroxide.
(Solved)
Describe how you would prepare crystals of sodium nitrate starting with 200cm3 of 2M
sodium hydroxide.
Date posted:
May 13, 2019
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Answers (1)
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The following table gives the melting points of oxides of elements in period 3. Study it and
answer the questions that follow:-
(Solved)
The following table gives the melting points of oxides of elements in period 3. Study it and
answer the questions that follow:-
(i) Explain the difference in melting points of MgO and P4O10
(ii) Name the compound in the above table that will dissolve both in dilute
hydrochloride acid and dilute sodium hydroxide.
Date posted:
May 13, 2019
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Answers (1)
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36cm3 of a solution of potassium hydroxide requires 25cm3 of 0.5M sulphuric acid to
neutralize it.Calculate the concentration of alkali in g/dm3
(Solved)
36cm3 of a solution of potassium hydroxide requires 25cm3 of 0.5M sulphuric acid to
neutralize it.Calculate the concentration of alkali in g/dm3
Date posted:
May 13, 2019
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Answers (1)
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The diagram below represents set-up that can be used to prepare and collect oxygen gas
(Solved)
The diagram below represents set-up that can be used to prepare and collect oxygen gas
a) Name solid P
b) What property of oxygen makes it possible for its collection as indicated by the
diagram.
c) Explain why it is important not to collect any gas for the first few seconds of the
experiment.
Date posted:
May 13, 2019
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Answers (1)
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During the electrolysis of dilute sulphuric (VI) acid the volume of hydrogen gas collected is twice
the volume of oxygen gas. Using half equations justify the...
(Solved)
During the electrolysis of dilute sulphuric (VI) acid the volume of hydrogen gas collected is twice
the volume of oxygen gas. Using half equations justify the above statement.
Date posted:
May 13, 2019
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Answers (1)
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Under certain conditions ,methane reacts with steam to form carbon (II) oxide and hydrogen only. Calculate the total volume of the gas that can be...
(Solved)
Under certain conditions ,methane reacts with steam to form carbon (II) oxide and hydrogen only. Calculate the total volume of the gas that can be formed when 100cm3 of steam reacts completely with methane.
Calculate the enthalpy change of the reaction.
Date posted:
May 13, 2019
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Answers (1)
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Using a suitable equation explain why it is not advisable to use hardwater in hot water
systems.
(Solved)
Using a suitable equation explain why it is not advisable to use hardwater in hot water
systems.
Date posted:
May 13, 2019
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Answers (1)
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The catalytic oxidation of ammonia gas is done as per the set up below.
(Solved)
The catalytic oxidation of ammonia gas is done as per the set up below.
a) Name the catalyst used in the above reaction.
b) After sometime, brown fumes are formed in the flask. Explain briefly how this
observation occurs.
c) Why does the metal catalyst stay red hot for some time?
Date posted:
May 13, 2019
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Answers (1)
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Hydrogen gas is one of the lightest gas known but has not lived to its expectation to be used inObservation balloons. Explain
(Solved)
Hydrogen gas is one of the lightest gas known but has not lived to its expectation to be used inObservation balloons. Explain
Date posted:
May 13, 2019
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Answers (1)
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Describe how you would prepare a sample of iron(II)carbonate,starting with iron metal and dilute hydrochloric acid.
(Solved)
Describe how you would prepare a sample of iron(II)carbonate,starting with iron metal and dilute hydrochloric acid.
Date posted:
May 13, 2019
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Answers (1)