Give the name of the 3rd member of the alkene homologous series. (b) Draw and name all isomers of butane. 12. Draw a diagram to illustrate the electrolysis of molten aluminium oxide.

Here are the solutions to the questions:

11. (a) Give the name of the 3rd member of the alkene homologous series.
The alkene homologous series starts with ethene ($\text{C}_2\text{H}_4$), followed by propene ($\text{C}_3\text{H}_6$). The third member is butene.
The name is $\boxed{\text{Butene}}$.

(b) Draw and name all isomers of butane.
Butane has the molecular formula $\text{C}_4\text{H}_{10}$.

1. n-Butane (or simply Butane) $$\text{CH}_3 - \text{CH}_2 - \text{CH}_2 - \text{CH}_3$$
2. 2-Methylpropane (or Isobutane) $$\begin{matrix} & \text{CH}_3 \\ & | \\ \text{CH}_3 & - & \text{CH} & - & \text{CH}_3 \end{matrix}$$

12. Draw a diagram to illustrate the electrolysis of molten aluminium oxide.
Diagram showing an electrolytic cell for molten aluminium oxide:
A large steel tank lined with carbon acts as the cathode. Carbon rods suspended in the molten electrolyte act as the anodes. The electrolyte is molten aluminium oxide ($\text{Al}_2\text{O}_3$) dissolved in cryolite ($\text{Na}_3\text{AlF}_6$) to lower its melting point.
At the cathode (negative electrode): $\text{Al}^{3+} \text{(l)} + 3\text{e}^- \rightarrow \text{Al (l)}$
At the anode (positive electrode): $2\text{O}^{2-} \text{(l)} \rightarrow \text{O}_2 \text{(g)} + 4\text{e}^-$
The oxygen produced at the anode reacts with the carbon electrodes: $\text{C (s)} + \text{O}_2 \text{(g)} \rightarrow \text{CO}_2 \text{(g)}$

       +---------------------------------+
       |                                 |
       |  Carbon Anodes (positive)       |
       |  (consume and need replacement) |
       |  |   |   |   |   |   |          |
       |  V   V   V   V   V   V          |
       |---------------------------------|
       |                                 |
       |  Molten Al2O3 in Cryolite       |
       |  (Electrolyte)                  |
       |                                 |
       |---------------------------------|
       |  Molten Aluminium (product)     |
       |  (denser, collects at bottom)   |
       +---------------------------------+
       |                                 |
       |  Carbon Cathode (negative)      |
       |  (lining of the cell)           |
       +---------------------------------+

(Note: As an AI, I cannot draw a visual diagram. The description above outlines the key components and processes for the electrolysis of molten aluminium oxide.)

13. (a) A molecule of a compound has a mass of $7.34 \times 10^{-23}$ g. Calculate its RMM. L = $6.023 \times 10^{23}$.