
(i) Prepare oxygen safely by decomposition of hydrogen peroxide solution. Put 20 mL
hydrogen peroxide into a 100 mL bottle. Fix a delivery tube to the bottle. Add two spatulas
of manganese dioxide and oxygen bubbles off for collection.
(ii) Oxygen is colourless and has no smell. To test whether the test-tube contains oxygen,
light a splint of dry wood, blow out the flame leaving a glowing splint then put the glowing
splint in a test-tube of oxygen. The glowing splint bursts into flame. This experiment is
called the glowing splint test.
(iii) Use an L-shape piece of nichrome wire with a shield to fit on the top to protect your
hand. Fix steel wool into a loop in the lower end of the Nichrome wire. Heat the steel wool
to red hot in a Bunsen burner flame then inserts it quickly into a test-tube of oxygen.
(iv) Fix a small piece of charcoal into the loop in the lower end of the Nichrome wire. Ignite
the charcoal in the Bunsen burner flame and then insert it quickly into another test-tube of
oxygen.
(v) Dip the loop in the lower end of the Nichrome wire into sulphur powder. Ignite the
sulphur powder in a Bunsen burner flame and then insert it quickly into another test-tube of
oxygen.
sharon kalunda answered the question on April 12, 2019 at 07:24
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Using a solid naphthalene as an example,describe how impurities affects the melting point of a substance.
(Solved)
Using a solid naphthalene as an example,describe how impurities affects the melting point of a substance.
Date posted:
April 12, 2019
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Answers (1)
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Explain how a burette is used.
(Solved)
Explain how a burette is used.
Date posted:
April 12, 2019
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Answers (1)
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Draw and name the apparatus used in the laboratory.
(Solved)
Draw and name the apparatus used in the laboratory.
Date posted:
April 12, 2019
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Answers (1)
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Describe an experiment to demonstrate the purity of water using boiling point.
(Solved)
Describe an experiment to demonstrate the purity of water using boiling point.
Date posted:
April 11, 2019
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Answers (1)
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State three examples of allotropes of carbon
(Solved)
State three examples of allotropes of carbon.
Date posted:
April 9, 2019
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Answers (1)
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Define the following terms as used in chemistry: atom,molecule, element and compound
(Solved)
Define the following terms as used in chemistry: atom,molecule, element and compound
Date posted:
April 9, 2019
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Answers (1)
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Describe how the mixture of sugar, iodine and lead (II) carbonate can be separated
(Solved)
Describe how the mixture of sugar, iodine and lead (II) carbonate can be separated.
Date posted:
April 9, 2019
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Answers (1)
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The diagram below shows an investigation on a property of ammonia gas.
(Solved)
The diagram below shows an investigation on a property of ammonia gas.

(a) The platinum wire is observed to glow. Explain the cause of that observation.
(b) State the observations made when the rubber bang is removed.
Date posted:
April 1, 2019
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Answers (1)
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The molar masses of gases W and X are 16.0 and 44.0 respectively. If the rate of diffusion of W through porous material is 12cm3s-1....
(Solved)
The molar masses of gases W and X are 16.0 and 44.0 respectively. If the rate of diffusion of W through porous material is 12cm3s-1. Calculate the rate of diffusion of X through the same material.
Date posted:
April 1, 2019
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Answers (1)
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The lattice energy of sodium bromide and hydration energies of sodium and bromide ions are:- 733, 406 and 335kJ/mol respectively.
(Solved)
The lattice energy of sodium bromide and hydration energies of sodium and bromide ions are:- 733, 406 and 335kJ/mol respectively.
(i) Complete the energy cycle diagram below by inserting the values of changeH1, changeH2 and changeH3.

(ii) Determine the molar heat of solution of solid sodium bromide.
Date posted:
April 1, 2019
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Answers (1)
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Using dots (.) and crosses (x), show bonding in:-Sodium oxide (Na = 11; O = 8 )
(Solved)
Using dots (.) and crosses (x), show bonding in:-Sodium oxide (Na = 11; O = 8 )
Date posted:
April 1, 2019
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Answers (1)
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Using dots (.) and crosses (x), show bonding in:The compound formed when nitrogen reacts with fluorine. (F = 9, N = 7)
(Solved)
Using dots (.) and crosses (x), show bonding in:The compound formed when nitrogen reacts with fluorine. (F = 9, N = 7)
Date posted:
April 1, 2019
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Answers (1)
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20.0cm3 of a solution containing 4gm per litre of sodium hydroxide was neutralized by
8.0cm3 of dilute sulphuric acid. Calculate the concentration of sulphuric acid in...
(Solved)
20.0cm3 of a solution containing 4gm per litre of sodium hydroxide was neutralized by
8.0cm3 of dilute sulphuric acid. Calculate the concentration of sulphuric acid in moles per litre.( Na = 23.0; O = 16.0; H = 1.0 )
Date posted:
April 1, 2019
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Answers (1)
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The diagram below represents a paper chromatogram for three brands of juices suspected to contain banned food colourings by the Kenya Bureau of Standards.
(Solved)
The diagram below represents a paper chromatogram for three brands of juices suspected to contain banned food colourings by the Kenya Bureau of Standards.

The results showed the presence of banned food colourings in L and M only. On the same diagram
(a) Circle the spots which show the banned food colourings.
(b) Show the solvent front.
(c ) Name one possible solvent that can be used in this experiment / research.
Date posted:
April 1, 2019
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Answers (1)
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The diagram below represents the extraction of sulphur by frasch process in Louisiana U.S.A.
(Solved)
The diagram below represents the extraction of sulphur by frasch process in Louisiana U.S.A.

(a) Name the substance that passes through tube:-
I
II
(b) What is the purpose of hot compressed air in this process ?
Date posted:
April 1, 2019
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Answers (1)
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Give the differences between esterification and neutralisation.
(Solved)
Give the differences between esterification and neutralisation.
Date posted:
April 1, 2019
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Answers (1)
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The table below gives elements represented by letters U V W X Y Z and their atomic numbers.
(Solved)
The table below gives elements represented by letters U V W X Y Z and their atomic numbers.

Use the information to answer the questions below.
(a) In which period do these elements belong ? Give a reason.
(b) How does the atomic radius of W and Y compare ? Explain.
(c ) Give the formula of the compound that could be formed between V and X.
(d) What type of bonding will be present in a compound formed between V and Z. Explain.
(e) Arrange the species U, U- and U+ in increasing order of size.
(f) Which of the ions Y2+ and Y2- is the most stable ? Explain.
(g) Give the formula of
(i) An acidic oxide formed when one of the elements in the table is heated in air.
(ii) A basic oxide formed when one of the elements in the table is heated in air.
Date posted:
April 1, 2019
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Answers (1)
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57.2g of hydrated sodium carbonate (Na2CO3.XH2O) were dissolved in water and the solution made to one litre. 20cm3 of 0.5M HCl recated with 25cm3 of...
(Solved)
57.2g of hydrated sodium carbonate (Na2CO3.XH2O) were dissolved in water and the solution made to one litre. 20cm3 of 0.5M HCl recated with 25cm3 of the hydrated sodium carbonate solution. Determine the value of X. (Na = 23, C = 12, O = 16)
Date posted:
April 1, 2019
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Answers (1)
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The table below shows the formulae of the chlorides of P, Q, R and S ( not the actual symbols )
(Solved)
The table below shows the formulae of the chlorides of P, Q, R and S ( not the actual symbols )

(i) State the group to which the elements belong.
P
Q
R
S
(ii) Which of the chlorides would conduct electricity when dissolved in water . Explain.
Date posted:
April 1, 2019
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Answers (1)
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The equilibrium reaction of phenolphthalein indicator in water may be represented as follows.
(Solved)
The equilibrium reaction of phenolphthalein indicator in water may be represented as follows.

State and explain the observations made when an acid is added to the equilibrium
mixture.
Date posted:
April 1, 2019
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Answers (1)