Suggested Answers and Discussion for the 2016 VCE Chemistry Exam

[shlblk]

pretty sure lithium is always soluble (correct me if i'm wrong?) - you should get a mark for the equations though!!

Lol. I just realised I had lithium oxide instead of lithium hydroxide in my equation. There's a silly mark gone.

[emilyb4398888]

pretty sure lithium is always soluble (correct me if i'm wrong?) - you should get a mark for the equations though!!

Yeah I;m not 100% I just knew that not all hydroxides are aq and took a guess!

[shlblk]

Do you reckon I'd still get a mark if I said that it produced hydrogen gas, which could cause an explosion, but went on to (stupidly) say that it caused lithium oxide as well?

I had oxide instead of hydroxide as well. I think we'd lose just 1 mark, as the part about hydrogen gas is still right.

[sweetcheeks]

Br2 and Cu react spontaneously according to electrochemical series so I'm pretty sure it's C!

Just because they react on the electrochemical series doesn't mean it will be observed. That is was A was implying.

[julijulib]

I had oxide instead of hydroxide as well. I think we'd lose just 1 mark, as the part about hydrogen gas is still right.

would i get two if i wrote the equation but didn't combine the lithium ions and the hydroxide ions?

[shlblk]

Just because they react on the electrochemical series doesn't mean it will be observed. That is was A was implying.

I agree, the reaction between copper and bromine could be extremely slow. To me it was between B and D. I ended up going with D though.

[julijulib]

Just because they react on the electrochemical series doesn't mean it will be observed. That is was A was implying.

damnnnnn so true, how does the grease affect it?

[shlblk]

would i get two if i wrote the equation but didn't combine the lithium ions and the hydroxide ions?

I think you'd still get full marks for that provided you had the explanation about hydrogen gas.

[shlblk]

damnnnnn so true, how does the grease affect it?

I didn't really see how grease would affect it at all, wasn't something I'd seen before. Hence why I went with D.

[BNard]

I wonder how harshly they'll mark the last question. I was a bit confused about how much detail to put in, seeing as they asked for 4 things but allocated 7 marks. Think mine might have been a bit on the short side, but surely can't get less than 4 if all my points were valid.

[julijulib]

What did people put for the strengths and weakness of the last question?
My strength was that she repeated the experiment (although i'm questioning that now seeing as she didn't calculate the result for all of them  )
And my two weaknesses were that she didn't keep checking the voltage and current throughout, and that she only patted the key dry and didn't weigh to constant mass... not sure if right, kinda rushed that bit!

[sweetcheeks]

damnnnnn so true, how does the grease affect it?

For a reaction to occur the iodine and copper must be able to be in contact. The grease should prevent contact between copper and iodine, stopping a reaction from occurring.

[shlblk]

What did people put for the strengths and weakness of the last question?
My strength was that she repeated the experiment (although i'm questioning that now seeing as she didn't calculate the result for all of them  )
And my two weaknesses were that she didn't keep checking the voltage and current throughout, and that she only patted the key dry and didn't weigh to constant mass... not sure if right, kinda rushed that bit!

I had the exact same, couldn't really think of anything else.

[Samm1]

What did people put for the strengths and weakness of the last question?
My strength was that she repeated the experiment (although i'm questioning that now seeing as she didn't calculate the result for all of them  )
And my two weaknesses were that she didn't keep checking the voltage and current throughout, and that she only patted the key dry and didn't weigh to constant mass... not sure if right, kinda rushed that bit!

I actually don't remember my strength but i mentioned not drying the key well and that an inert electrode wasn't used (not sure on the last part).

[julijulib]

For a reaction to occur the iodine and copper must be able to be in contact. The grease should prevent contact between copper and iodine, stopping a reaction from occurring.

Hmm, so i guess it must be b. It's so annoying how in exam situations common sense and clarity often goes out the window..