-Boiling and melting points of alkali metals decreases down the group due to increase in
atomic radius thus reducing the nuclear force of attraction
- melting and boiling points of halogens increase due to increase in the molecular size that
requires more energy to break.
sharon kalunda answered the question on May 16, 2019 at 12:48
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Helium is used instead of Hydrogen to fill balloons.Explain
(Solved)
Helium is used instead of Hydrogen to fill balloons.Explain
Date posted:
May 16, 2019
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Answers (1)
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A solution containing 0.1m sulphuric acid has a pH of 2 while 5M has a pH of more than two.
Explain.
(Solved)
A solution containing 0.1m sulphuric acid has a pH of 2 while 5M has a pH of more than two.
Explain.
Date posted:
May 16, 2019
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Answers (1)
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State and explain the observation made in the set-up below.
(Solved)
State and explain the observation made in the set-up below.
Date posted:
May 16, 2019
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Answers (1)
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A mixture of carbon (IV) Oxide and carbon (II) oxide is passed through potassium hydroxide
solution as shown in the following set up.
(Solved)
A mixture of carbon (IV) Oxide and carbon (II) oxide is passed through potassium hydroxide
solution as shown in the following set up.
I) Name gas X
(ii) Why should gas X be burned.
(iii) Write a well balanced chemical equation for the reaction that takes place in the conical
flask in the first few seconds.
Date posted:
May 16, 2019
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Answers (1)
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Write ionic equations for electrolysis of dilute sulphuric acid using platinum electrodes at:
(Solved)
Write ionic equations for electrolysis of dilute sulphuric acid using platinum electrodes at:
(i) Anode
(ii) Cathode
Date posted:
May 16, 2019
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Answers (1)
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100cm3 of 2M Nitric acid reacted with 12.5g of a carbonate MCO3 of metal M, calculate the relative atomic mass of M ( C =...
(Solved)
100cm3 of 2M Nitric acid reacted with 12.5g of a carbonate MCO3 of metal M, calculate the relative atomic mass of M ( C = 12, O = 16)
Date posted:
May 16, 2019
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Answers (1)
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A white solid K was heated. It produced a brown gas A and another gas B which relights a
glowing splint. The residue left was yellow...
(Solved)
A white solid K was heated. It produced a brown gas A and another gas B which relights a
glowing splint. The residue left was yellow even after cooling.
a) Identify gases A and B
b) Write a balanced chemical equation for the decomposition of solid K.
Date posted:
May 16, 2019
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Answers (1)
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Below is a set up used to collect hydrogen gas.
(Solved)
Below is a set up used to collect hydrogen gas.
a) Identify with reasons, two mistakes in the set up.
b) Explain the role of hydrogen in the manufacture of margarine.
Date posted:
May 16, 2019
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Answers (1)
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The scheme below shows some reaction sequence starting with solid M
(Solved)
The scheme below shows some reaction sequence starting with solid M
(i) Name Solid M
(ii) Write the formula of complex ion present in Solution Q
(iii) Write ionic equation of reaction between barium nitrate and solution N.
Date posted:
May 16, 2019
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Answers (1)
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What is the oxidation number of chlorine in ClO-4?
(Solved)
What is the oxidation number of chlorine in ClO-4?
Date posted:
May 16, 2019
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Answers (1)
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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)