Allotropes of carbon.
Graphite:one of the softest known substance, opaque and a good lubricant.
Diamond: hardest naturally occurring substance.
Buckyballs(fullerence)
Amorphous carbon
Glassy carbon
Carbon nanofoam
Nanotubes
jameskimwe answered the question on April 10, 2019 at 09:28
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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)
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The diagram below shows the appearance of two pieces of paper placed in different parts of a non-luminous flame of a Bunsen burner and removed...
(Solved)
The diagram below shows the appearance of two pieces of paper placed in different parts of a non-luminous flame of a Bunsen burner and removed quickly before they caught fire.

(a) What do the experiments show about the outer region of the flame?
(b) From the above experiment, which part of the flame is better to use for heating? Give a reason
Date posted:
March 29, 2019
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Answers (1)
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Ammonia gas was passed into water as shown below.
(Solved)
Ammonia gas was passed into water as shown below.

(a) When a red litmus paper was dropped into the resulting solution; it turned blue.Give a reason to this observation.
(b) What is the function of the funnel?
Date posted:
March 29, 2019
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Answers (1)
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The following diagram represents a set-up that can be used in the laboratory to prepare and collect a sample of chlorine gas:
(Solved)
The following diagram represents a set-up that can be used in the laboratory to prepare and collect a sample of chlorine gas:

a)No gas bubbles were produced in the above experiment. Explain the observation.
(b) Complete the following equation.
Cl2(g) + H2O(l)---------->
(c) Describe the bleaching property of chlorine water
Date posted:
March 29, 2019
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Answers (1)
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During purification of copper by electrolysis, 1.48g of copper were deposited when a current was passed through aqueous copper (II) sulphate for 2 ½ hours....
(Solved)
During purification of copper by electrolysis, 1.48g of copper were deposited when a current was passed through aqueous copper (II) sulphate for 2 ½ hours. Calculate the amount of current that was passed.(Cu = 63.5; IF = 96500C)
Date posted:
March 29, 2019
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Answers (1)
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Two experiments were carried out as follows and the volume of hydrogen gas evolved measured at intervals of 10 seconds for 100 seconds.
(Solved)
Two experiments were carried out as follows and the volume of hydrogen gas evolved measured at intervals of 10 seconds for 100 seconds.
i) 8cm of magnesium ribbon was added to 1M HCl(aq)
(ii) 8cm of magnesium ribbon was added to 0.5M HCl(aq)
Graphs of volume of hydrogen gas evolved against time were plotted as shown below.

a) Which of the graphs was obtained for reaction (i). Explain.
(b) Explain the general shape of the graphs.
Date posted:
March 29, 2019
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Answers (1)