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Cheptoo set-up some apparatus as shown in the diagram below:-
(Solved)
Cheptoo set-up some apparatus as shown in the diagram below:-
At the start of the experiment, the bulb did not light:-
(a) State and explain the observation made when the tap was opened to allow the hydrogen chloride gas through the water for about 20 minutes
(b) Write the chemical equation for the reaction that took place at the cathode
Date posted:
October 31, 2019
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Answers (1)
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The flow chart below shows an analysis of mixture R that contains two salts. Study it and answer the questions that follow:-
(Solved)
The flow chart below shows an analysis of mixture R that contains two salts. Study it and answer the questions that follow:-
(i) Write two ionic equations for the reactions between the cation in filtrate X and aqueous
ammonia (Ammonium hydroxide)until in excess
(ii) What conclusion can be drawn from Step IV only? Explain
(iii) What observation would indicate the presence of a NO3- ion in step I?
(iv) Write the formula of the anion in residue V. Explain
(v) Suggest the identity of the cation present in solution Z
(vi) Name the two salts present in mixture R
Date posted:
October 29, 2019
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Answers (1)
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When nitrate solution of a certain metal X was electrolysed, 1.174g of metal X was deposited by a current of 4 amperes flowing for 16...
(Solved)
When nitrate solution of a certain metal X was electrolysed, 1.174g of metal X was deposited by a current of 4 amperes flowing for 16 minutes. Determine the formula of the metal nitrate. (1F= 96,500, R.A.M of X= 59)
Date posted:
October 29, 2019
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Answers (1)
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The standard electrode potential for the elements chlorine and magnesium are:-
(Solved)
The standard electrode potential for the elements chlorine and magnesium are:-
Which one of the two elements will act as an oxidizing agent? Explain.
Date posted:
October 29, 2019
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Answers (1)
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The table gives the standard redox potentials for a number of half reactions. Use it to answer the questions that follow:-
(Solved)
The table gives the standard redox potentials for a number of half reactions. Use it to answer the questions that follow:-
(i) Relative to which half-cell reaction are the above electrode potentials expressed?
(ii) Calculate the e.m.f of the cell made up by combining the 
electrode and 
electrode
(iii) Which of the substances listed in the above table is :-
I. The strongest oxidising agent
II. The strongest reducing agent
(iv) Which substances could be used to convert iodide ions to iodine? Write balanced equations for any possible conversions
Date posted:
October 29, 2019
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Answers (1)
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Study the standard electrode potential for the half-cells given below and answer the questions that follow.(The letter do not represent the actual symbols of the...
(Solved)
Study the standard electrode potential for the half-cells given below and answer the questions that follow.(The letter do not represent the actual symbols of the elements)
i) Identify the strongest oxidizing agents. Give a reason for your answer
ii) Which two half-cells would produce the highest potential difference when combined?
iii) In the space below draw a complete electro-chemical cell of the two-half cells mentioned
in (ii) above
Date posted:
October 29, 2019
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Answers (1)
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Study the flow chart below and answer the questions that follow:
(Solved)
Study the flow chart below and answer the questions that follow:
(a) Name gas Q
(b) With the help of diagram, describe how step (V) is carried out
Date posted:
October 29, 2019
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Answers (1)
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What mass of Zinc will be deposited from a solution of Zinc (II) Chloride when a current of 3A is passed through the Zinc (II)...
(Solved)
What mass of Zinc will be deposited from a solution of Zinc (II) Chloride when a current of 3A is passed through the Zinc (II) Chloride solution during electrolysis for 50 minutes?
(Zn= 65, 1 Faraday = 96500C)
Date posted:
October 29, 2019
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Answers (1)
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In an electrolysis, a current of 200A was passed through molten oxide of metal Q for 58 minutes and 64.8g of the metal deposited. Determine;
i)...
(Solved)
In an electrolysis, a current of 200A was passed through molten oxide of metal Q for 58 minutes and 64.8g of the metal deposited. Determine;
i) Charge on metal Q
ii) The volume of oxygen gas produced at standard temperature and pressure
Q = 27 IF = 96500C, molar gas volume stp =22.4dm3
Date posted:
October 29, 2019
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Answers (1)
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The following is a thermochemical equation for the reaction between hydrogen and oxygen
(Solved)
The following is a thermochemical equation for the reaction between hydrogen and oxygen
Calculate the bond energy between the elements in water given that:
Date posted:
October 29, 2019
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Answers (1)
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The graph below represents the volume of gas collected against time when dilute sulphuric acid is reacted with Zinc granules:-
(Solved)
The graph below represents the volume of gas collected against time when dilute sulphuric acid is reacted with Zinc granules:-
(a) Determine the rate of reaction between the 1st and 3rd minute
(b) When did the reaction stop?
(c) Give a possible reason for the reaction to stop
Date posted:
October 29, 2019
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Answers (1)
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The sketch below was obtained when 2g of magnesium was reacted with excess of 2M hydrochloric acid. The volume of hydrogen evolved was then plotted...
(Solved)
The sketch below was obtained when 2g of magnesium was reacted with excess of 2M hydrochloric acid. The volume of hydrogen evolved was then plotted against time as shown below:
(a) On the same axis plot the graph that would be obtained if 1M hydrochloric acid was used instead of 2M hydrochloric acid. Explain
(b) Explain the significance of the flat portion BC of the curve
Date posted:
October 28, 2019
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Answers (1)
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Study the diagram below and answer the questions that follow:
(Solved)
Study the diagram below and answer the questions that follow:
Date posted:
October 28, 2019
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Answers (1)
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Iodine can react with chlorine as shown below:-
(Solved)
Iodine can react with chlorine as shown below:-
Determine the molar enthalpy change for this reaction
Date posted:
October 28, 2019
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Answers (1)
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The equation below represents changes in the physical state of ions metal:
(Solved)
The equation below represents changes in the physical state of ions metal:
Calculate the amount of heat energy required to change 10kg of solid iron to gaseous iron
Fe = 56
Date posted:
October 28, 2019
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Answers (1)
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The setup below was used to investigate the changes that take place when sodium hydroxide pellets dissolve in water.
(Solved)
The setup below was used to investigate the changes that take place when sodium hydroxide pellets dissolve in water.
a) Why is a plastic beaker used instead of a metallic beaker?
b) State and explain the observations made in the above reaction
Date posted:
October 28, 2019
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Answers (1)
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Biogas is a mixture of mainly Carbon (IV) Oxide and methane.
(i) Give a reason why biogas can be used as a fuel
(ii) Other than fractional...
(Solved)
Biogas is a mixture of mainly Carbon (IV) Oxide and methane.
(i) Give a reason why biogas can be used as a fuel
(ii) Other than fractional distillation, describe a method that can be used to determine the percentage of methane in biogas
Date posted:
October 28, 2019
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Answers (1)
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A typical electrolysis cell uses a current of 40,000 amperes. Calculate the mass (in Kg of aluminium produced in one hour). (Al = 27) (Faraday...
(Solved)
A typical electrolysis cell uses a current of 40,000 amperes. Calculate the mass (in Kg of aluminium produced in one hour). (Al = 27) (Faraday = 96500 Coloumbs)
Date posted:
October 28, 2019
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Answers (1)
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When 1.6g of ammonium nitrate were dissolved in 100cm3 of water, the temperature dropped by 6ºC. Calculate its enthalpy change. (Density of water = 1g/cm3,specific...
(Solved)
When 1.6g of ammonium nitrate were dissolved in 100cm3 of water, the temperature dropped by 6ºC. Calculate its enthalpy change. (Density of water = 1g/cm3,specific heat capacity is 4.2kJ kg-1K-1)
Date posted:
October 28, 2019
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Answers (1)
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Nitrogen and hydrogen react reversibly according to the equation:-
(Solved)
Nitrogen and hydrogen react reversibly according to the equation:-
The energy level diagram for the above reaction is shown below:-
(a) How would the yield of ammonia be affected by:
(i) A decrease in temperature
(ii) An increase in pressure
(b) How does a catalyst affect reversible reaction already in equilibrium?
(c) On the above diagram, sketch the energy level diagram that would be obtained when iron catalyst is added to the reaction
Date posted:
October 28, 2019
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Answers (1)