It's very difficult to find good ready-to-download answers for past papers. The marker's guides aren't helpful at all. They focus on what the students failed to do rather than what they did that was correct.
You would choose a specific polymer and talk about it. Give examples of other biopolymers too. Then point out the stumbling blocks - i.e. what is preventing large-scale production of these biopolymers? These could be disadvantages such as cost and efficiency. Sum up with a line or two, making it clear how successful the biopolymer industry has been in replacing non-biodegradable material.
This is because alkenes are unsaturated compounds - they have a double bond which make them a lot more reactive than the saturated alkanes. Because of this, alkenes readily undergo addition reactions to form other substances, while alkanes can only undergo substitution reactions with certain compounds under certain conditions (e.g. reacting with chlorine in the presence of U.V. radiation).
However, alkanes and their corresponding alkenes have very similar boiling and melting points (physical properties) because these properties depend on the intermolecular, not intramolecular forces. Alkanes and corresponding alkenes have very similar atomic masses, and are non-polar compounds. Hence the only intermolecular force present are weak dispersion forces.
You can look this up in a textbook. I did the silver-oxide (button) cell which I found relatively easy. You should include in your answer the anode and cathode reactions, and shorthand diagrams.
By comparing the environmental impacts, you focus on the chemicals used in the cells, and those that are released by the cells once they are thrown away. For example, the alkaline cell presents a more severe environmental problem than the zinc-carbon cell, because alkaline waste is more dangerous to waterways. Impacts on society means the size of the cell, how long it lasts, and what appliances it is suitable for.
I've answered all of these questions when I was going through past papers during the HSC. Just use all the information in your head. Write as much as you can (during the limited time) and make sure you don't contradict yourself. For these types of questions, you can choose to put them into dot points. For the battery question, a table may be appropriate.
