Revision Worksheet

THE WESTMINSTER SCHOOL, DUBAIDEPARTMENT OF CHEMISTRY

Year: Section: .. Revisit Assessment Task sheet Name : . Date: .

1.Rewrite the following equations as an ionic equation.a) Mg + H2SO4 MgSO4+ H2 b) Ca + 2 HCl CaCl2 + H2 c) 2 NaBr + Cl2 2 NaCl + Br2.

Butene Hydrogen Butane(i) Complete the table [2]BondBond energy in KJ/molExothermic/Endothermic

C=C broken610..

H-H broken436..

C-C formed346..

C-H formed413.

(ii) Which among the two bonds: C-C or C=C is stronger? .[1]

(iii) Use the bond energy to determine the reaction is endothermic or exothermic. Bonds broken are ., , ., .. Energy taken in to break bonds= .. Bonds formed are .., .., Energy given out when bonds are made= .. Overall heat of reaction= .... [5]

3.

(i) Define cell. [1](ii) Write ionic equation for the reaction 1 . [1] (iii) Complete the equation for the reaction at the oxygen electrode

O2 + .. [1](iv) Suggest on which electrode reduction takes place. Give a reason for your choice of answer..

. [2]

4.

5. Aluminium is extracted by the electrolysis of a mixture of molten oxide and cryolite.

(a) Name the main ore of aluminium. [1] (b) Why does the molten electrolyte contain cryolite? [2] (c) Write the overall equation for this electrolysis. [2] (d) The graphite anodes have to be renewed periodically. Explain why and write any relevant equations. [2]

6.

7.

8.

9

10