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One use of electrolysis is electroplating as shown below.
(Solved)
One use of electrolysis is electroplating as shown below.
(i) To what terminal of the power source is the key connected
(ii) Name the most suitable material for electrode K
(iii) Write the
(iv) If 3A power source was used for 5 hours, calculate the increase in mass of the Key.
( Ag = 108, 1 Fa=96500C)
Date posted:
May 21, 2019
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Answers (1)
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State the particles responsible for conductivity of an electric current in
(i) Solution
(ii) A metal
(Solved)
State the particles responsible for conductivity of an electric current in
(i) Solution
(ii) A metal
Date posted:
May 21, 2019
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Answers (1)
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The scheme below shows a series of reactions starting with Propanol. Study it and answer the questions that follow.
(a) (i) Name the type of reaction...
(Solved)
The scheme below shows a series of reactions starting with Propanol. Study it and answer the questions that follow.
(a) (i) Name the type of reaction in steps I and II
(b) Write the equation for the reaction that takes place in Step III
(c) Name substances labeled A,C,D and E
(d) Draw the structural formula of product C .
(e) Name the process in Step (IV).
(f) Name compound B and state the type of reaction involved in its formation
Name of compound B……………………………………………………………
Type of reaction………………………………………………………………….
(g) If the relative molecular mass of B is 35,700 determine the value of n
Date posted:
May 21, 2019
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Answers (1)
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Study the diagram below and use it to answer the questions that follow.
(i) Name liquids A and B
(ii) Suggest a suitable reagent that can be...
(Solved)
Study the diagram below and use it to answer the questions that follow.
(i) Name liquids A and B
(ii) Suggest a suitable reagent that can be used as solid D
(iii) State the role of Solid D
(iv) Write a balanced chemical equation for the reaction in the conical flask
(v) Explain why solid C collects further away from the heated aluminium metals.
Date posted:
May 20, 2019
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Answers (1)
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The table below shows some properties and electronic arrangement of ions of elements represented by letters P to X. Study the information and answer the...
(Solved)
The table below shows some properties and electronic arrangement of ions of elements represented by letters P to X. Study the information and answer the questions that follow. The letters are not the actual symbols of elements.
(i) Give the atomic numbers of elements T and V
(ii) What is the name given to the family of elements to which R,V and W belong.
(iii) Explain why:
I .The atomic radius of S is smaller than that of V
II. the atomic radius of R is larger than its ionic radius
(iv) Using dots (•) and crosses (x) to represent outermost electrons, show the bonding in
the compound formed between U and X
(v) Describe how a mixture of V chlorine s Lead(II) chloride can be separated
Date posted:
May 20, 2019
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Answers (1)
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Determine the relative atomic mass of the argon whose isotopic mixture is:
(Solved)
Determine the relative atomic mass of the argon whose isotopic mixture is:
Date posted:
May 20, 2019
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Answers (1)
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40cm3of carbon(II) oxide and 40 cm3 of oxygen were sparked in a closed vessel.
(i) Write a chemical equation for the reaction that occurs.
(ii) Determine...
(Solved)
40cm3of carbon(II) oxide and 40 cm3 of oxygen were sparked in a closed vessel.
(i) Write a chemical equation for the reaction that occurs.
(ii) Determine the composition of the residual gases.
Date posted:
May 20, 2019
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Answers (1)
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The main ore of copper is low grade. Describe how the main ore can be concentrated.
(Solved)
The main ore of copper is low grade. Describe how the main ore can be concentrated.
Date posted:
May 20, 2019
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Answers (1)
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Name and give the chemical formula of the chief ore of copper.
(Solved)
Name and give the chemical formula of the chief ore of copper.
Date posted:
May 20, 2019
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Answers (1)
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The graphs below represents the temperature-time curves for solids M and N
(Solved)
The graphs below represents the temperature-time curves for solids M and N
(a) What is the name given to the curves above?.
(b) Which of the two solids is an impure substance? Explain.
Date posted:
May 20, 2019
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Answers (1)
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State one large scale use of sulphuric (VI) acid
(Solved)
State one large scale use of sulphuric (VI) acid
Date posted:
May 20, 2019
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Answers (1)
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Nelly’s lungs can hold 2500cm3 of air at 37oC and 1 atmosphere. What would be the pressure if this air was put in a bottle...
(Solved)
Nelly’s lungs can hold 2500cm3 of air at 37oC and 1 atmosphere. What would be the pressure if this air was put in a bottle of capacity 500cm3 at 27oC?
Date posted:
May 20, 2019
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Answers (1)
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Explain why galvanized iron objects are better protected even when scratched.
(Solved)
Explain why galvanized iron objects are better protected even when scratched.
Date posted:
May 20, 2019
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Answers (1)
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Painting, oiling, galvanizing or tin-plating are methods of preventing rusting.Explain how these methods are similar in the way they prevent rusting.
(Solved)
Painting, oiling, galvanizing or tin-plating are methods of preventing rusting.Explain how these methods are similar in the way they prevent rusting.
Date posted:
May 20, 2019
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Answers (1)
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The following set up was used to react steam with Iron Powder.
(a) The water was heated before heating the iron powder. Explain why this was...
(Solved)
The following set up was used to react steam with Iron Powder.
(a) The water was heated before heating the iron powder. Explain why this was necessary.
(b) Write an equation for the reaction that took place between steam and iron powder
(c) State how gas L would be collected without using water.
Date posted:
May 20, 2019
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Answers (1)
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25cm3 of 0.1m sulphuric (VI) acid required 20cm3 of sodium carbonate solution for complete neutralization. Calculate the concentration of sodium carbonate in moles per litre.
(Solved)
25cm3 of 0.1m sulphuric (VI) acid required 20cm3 of sodium carbonate solution for complete neutralization. Calculate the concentration of sodium carbonate in moles per litre.
Date posted:
May 20, 2019
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Answers (1)
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The graph below represents the solubility curve of a gas in water.
(a) State and explain the conclusion that can be drawn from this curve about...
(Solved)
The graph below represents the solubility curve of a gas in water.
(a) State and explain the conclusion that can be drawn from this curve about the
solubility of the gas.
(b) The solubility of potassium chlorate at 80oC is 40g/100g of water. What mass of potassium chlorate will saturate 65g of water at 80oC.
Date posted:
May 20, 2019
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Answers (1)
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Iron is extracted from its ore, hematite in the blast furnace. The main reaction during
extraction is shown by the equation below;
Calculate the mass of iron...
(Solved)
Iron is extracted from its ore, hematite in the blast furnace. The main reaction during
extraction is
Calculate the mass of iron which will be produced from 320 tonnes of hematite.
(Fe= 56 O=16)
Date posted:
May 20, 2019
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Answers (1)
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6.5 g of zinc granules were reacted with 25cm3 of 4M hydrochloric acid. The graph below shows
the results:
(a) How long did it take for...
(Solved)
6.5 g of zinc granules were reacted with 25cm3 of 4M hydrochloric acid. The graph below shows
the results:
(a) How long did it take for the reaction to be complete?
(b) Calculate the average rate of reaction.
Date posted:
May 20, 2019
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Answers (1)
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Flourine has very low melting and boiling points and yet its atoms are joined by covalent bonding. Explain.
(Solved)
Fluorine has very low melting and boiling points and yet its atoms are joined by covalent
bonding. Explain.
Date posted:
May 20, 2019
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Answers (1)