FAQ for the Chemistry exam

[merlin]

Significant figures and states
Every paper has 1 mark for significant figures, and 1 mark for states. This means you can only lose 1 mark maximum, due to incorrectly doing your significant figures or states, but for those seeking to obtain these marks - don't fret. They only check one question to decide whether you pick up the mark or not. It is usually indicated by the question that says "express your answer to the appropriate number of significant figures" or "show all states." That will be the question they check for states, and they won't care about anything else, unless you state absurd amounts of significant figures.

I've seen some questions that say 'u are not required to show states', so does that mean questions such as:
  'write the overall reaction', mean u need to show states or else u lose 1 mark?

[bec]

As a rule, I would always show states...they won't mark you down for putting them in (would they?) and it doesn't take up too much time.

A couple of questions - I've read the study design but I'm still unclear about how much we need to know about specific equations. How did everyone else interpret it?

For example, if we studied sulfuric acid will we need to know the equation that produces superphosphate, for fertiliser? Or, would we need to know the exact reactions that take place in alkaline cells, etc?

[Collin Li]

For example, if we studied sulfuric acid will we need to know the equation that produces superphosphate, for fertiliser? Or, would we need to know the exact reactions that take place in alkaline cells, etc?

Using a bit of logic, I think it is almost impossible. The question on your chemical of choice will be generic. They cannot corner you into writing the equation of sulfuric acid's role in fertiliser production, because it wouldn't be applicable to say, ethene.

As far as I know, you do not need to know the exact reactions that take place in the plethora of cells that you're presented. The textbooks aren't consistent with which ones they cover, nor does the study design specify which ones should be covered. I would focus more on fuel cells (a new dot point arose on the advantages and disadvantages of them), and if anything, the lead-acid secondary cell, perhaps.

[pfftlah]

hey do you think we think to know the details of the different types of electrolytic cells, such as Down, Aluminium, etc? my teacher seems to think we need to, as well as 2 different types of primary and secondary cells [including equations if i remember correctly].
it's doubtful they'd ask us to recall something specific about these different types of cells, right?

[pinchies]

On the old course yes, but i don't think we need to be as familiar with them now. Doesn't hurt to understand it at least.

[NGUB]

I have a question, I've been wondering that which primary cells, secondary cell as well as Fuel cell that u need to remember for the exam, i know that we don't need to learn them by heart (the half equations), but like some of them, it costs time to work out the half equation, so can u guys suggest some cells that we should learn???

[shinny]

hydrogen-oxygen fuel cell perhaps...but overall, I'm not too keen on necessarily memorising anything. Deriving things on the spot often prevents errors rather than causing them through incorrect memorisation/recalling. This is of course, unless you're not too great at the principles of chem itself, but otherwise, I'd say just work out everything on the spot since you're able to. Saves you time memorising stuff you don't need really. There's plenty of time in the chem unit 4 exam from what I've seen anyway.

[NGUB]

Can i ask sth to comfirm, so we only need to choose 1 chemical to study right??? LIKE IF I CHOOSE SULFURIC ACID, I DON'T EVEN NEED TO KNOW THE OTHER ONE RIGHT?? LIKE I DON'T EVEN NEED TO LOOK AT THEM??? OR NOT???

[Matt The Rat]

It'll most likely ask you to state your chemical, then answer the generic questions which follow.

[Collin Li]

Can i ask sth to comfirm, so we only need to choose 1 chemical to study right??? LIKE IF I CHOOSE SULFURIC ACID, I DON'T EVEN NEED TO KNOW THE OTHER ONE RIGHT?? LIKE I DON'T EVEN NEED TO LOOK AT THEM??? OR NOT???

You only need to know 1 chemical. There will be the same one question for every chemical - it will apply be generic enough to apply to any chemical.

[NGUB]

THANKS!!!

[Blakhitman]

Significant figures and states
Every paper has 1 mark for significant figures, and 1 mark for states. This means you can only lose 1 mark maximum, due to incorrectly doing your significant figures or states, but for those seeking to obtain these marks - don't fret. They only check one question to decide whether you pick up the mark or not. It is usually indicated by the question that says "express your answer to the appropriate number of significant figures" or "show all states." That will be the question they check for states, and they won't care about anything else, unless you state absurd amounts of significant figures.

OMG, is this still the same now? I am so relieved reading this, I always make a mistake with this.