To prevent it from reacting with air and water
johnmulu answered the question on February 21, 2017 at 06:26
- Explain why it is not advisable to use wood ash for cleaning aluminium utensils
and state the advantage of using duralumin in place of aluminium for manufacture of aeroplane n parts
(Solved)
a) Explain why it is not advisable to use wood ash for cleaning aluminium utensils
b) Duralumin is an alloy of aluminium. What is the advantage of using duralumin in place of aluminium for manufacture of aeroplane parts
Date posted: February 21, 2017. Answers (1)
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State two uses of copper
Date posted: February 21, 2017. Answers (1)
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State two applications of electrolysis.
Date posted: February 20, 2017. Answers (1)
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Calculate the time in minutes required to deposit 1.184 g of copper if a current of 2 amperes was used. (1 Faraday = 96500 coulombs, Cu = 63.5).
Date posted: February 18, 2017. Answers (1)
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A student electroplated a spoon with copper metal. Write an equation for the process that took place at the cathode.
Date posted: February 18, 2017. Answers (1)
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Hydrogen and oxygen can be obtained by electrolysis of acidified water. Using equations for the reactions at the electrodes, explain why the volume of hydrogen obtained is twice that of oxygen.
Date posted: February 18, 2017. Answers (1)
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State and explain the observations made when a copper rod is placed in a beaker containing silver nitrate solution.
Date posted: February 16, 2017. Answers (1)
- During the electrolysis of aqueous silver nitrate, a current of 5.0 A was passed through the electrolyte for 3 hours.(Solved)
During the electrolysis of aqueous silver nitrate, a current of 5.0 A was passed through the electrolyte for 3 hours.
a) Write the equation for the reaction which took place at the anode
b) Calculate the mass of silver deposited. (Ag = 108; IF = 96500 C)
Date posted: February 16, 2017. Answers (1)
- When brine is electrolysed using inert electrodes, chlorine gas is liberated at the anode instead of oxygen. Explain this observation and name the product formed at the cathode.(Solved)
a) When brine is electrolysed using inert electrodes, chlorine gas is liberated at the anode instead of oxygen. Explain this observation.
b) Name the product formed at the cathode.
Date posted: February 16, 2017. Answers (1)
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State how the following substances conduct electricity:
i) Molten calcium chloride
ii) Graphite
Date posted: February 16, 2017. Answers (1)
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Date posted: February 16, 2017. Answers (1)
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When a current of 0.82 A was passed for 5 hours through an aqueous solution of metal Z, 2.65 g of the metal were deposited. (1 Faraday = 96500 Coulombs: Relative atomic mass of Z = 52)
(a) Calculate the number of faradays used.
(b) Determine the charge on the ion of metal P.
(c) Write the equation for the formation of ion of P.
Date posted: February 16, 2017. Answers (1)
- Brine usually contains soluble calcium and magnesium salts. Explain how sodium carbonate is used to purify brine(Solved)
Brine usually contains soluble calcium and magnesium salts. Explain how sodium carbonate is used to purify brine
Date posted: February 16, 2017. Answers (1)
- During purification of copper by electrolysis, 1.48 g of copper were deposited when current was passed through aqueous copper (II) sulphate for 2$\frac{1}{2}$ hours. Calculate the amount of current used. (Cu = 63.5; 1 F = 96500 C(Solved)
During purification of copper by electrolysis, 1.48 g of copper were deposited when current was passed through aqueous copper (II) sulphate for 2$\frac{1}{2}$ hours. Calculate the amount of current used. (Cu = 63.5; 1 F = 96500 C).
Date posted: February 16, 2017. Answers (1)
- An element P has a relative atomic mass of 88. When a current of 0.5 amperes was passed through the fused chloride of P for 32 minutes and 10 seconds, 0.44 g of P were deposited at the cathode.(Solved)
An element P has a relative atomic mass of 88. When a current of 0.5 amperes was passed through the fused chloride of P for 32 minutes and 10 seconds, 0.44 g of P were deposited at the cathode. Determine the charge on an ion of P.
(1 Faraday = 96500 Coulombs)
Date posted: February 16, 2017. Answers (1)
- When a current of 1.5 amperes was passed through a cell containing M3+ ions of metal M for 15 minutes, the mass of the cathode increases by 0.26 g. (1 Faraday = 96500 coulombs). (Solved)
When a current of 1.5 amperes was passed through a cell containing M3+ ions of metal M for 15 minutes, the mass of the cathode increases by 0.26 g. (1 Faraday = 96500 coulombs).
a) Calculate the quantity of electricity used
b) Determine the relative atomic mass of metal M.
Date posted: February 16, 2017. Answers (1)
- Give reason why aluminium metal would protect iron from rusting better than zinc metal(Solved)
Give reason why aluminium metal would protect iron from rusting better than zinc metal.
Date posted: February 16, 2017. Answers (1)
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Aqueous potassium sulphate was electrolyzed using platinum electrodes in a cell.
a) Name the products formed at the cathode and anode
b) How does the concentration of the electrolyte change during electrolysis?
c) Why would it not be advisable to electrolyse aqueous potassium sulphate using potassium metal electrodes?
Date posted: February 16, 2017. Answers (1)
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Other than concentration, state two factors that determine the rate of a reaction.
Date posted: February 16, 2017. Answers (1)
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Explain why it is not advisable to use aqueous sodium chloride solution as the salt bridge in the electrochemical cell formed between half cells, Pb2+(aq)/Pb(s) Eo = - 0.13 V and Cu2+(aq)/Cu(s) Eo = + 0.34 V.
Date posted: February 16, 2017. Answers (1)