Can we just ignore nitrates and sulfates dissolved in an electrolyte when we're deducing cell reactions?
How does the bond strength of the reactants or products relate to whether a reaction is endo- or exothermic? I've had a few questions ask about the strength of the bond in hydrogen and oxygen (undergoing combustion) compared to the strength of the O-H bonds in the water formed... how're we supposed to know which molecule contains the stronger bonds?
Why is electrolysing an aqueous NaCl solution more desirable than just electrolysing pure water? I get that we need charged particles to conduct electricity, but why? Just an expression thing as well - do we say the we electrolyse whatever the electrolyte is (eg. the NaCl solution was electrolysed) or whatever is specifically reacting (eg. magnesium was electrolysed)
When is it possible to determine K without a volume? I know in one VCAA exam there was a question where you could figure out K from the number of moles, but in another exam (Insight, I think), the answer was that K could not be determined without a volume
Is cell voltage affected by the electrolyte concentration (would it increase if we increased the concentration)?
Thanks 
1) Generally you can, however they like to ask oh sulfate ion is an oxidant, how come it isn't reduced. Well you need acidic conditions to start, and to be reduced that would occur at the cathode in electrolysis, the cathode is negative so the sulfate ion wouldn't be electrostatically attracted to the electrode!!
2) Think of combustion like a massive explosion, you come from something fabulous like glucose down to basics like CO2 and H2O. In something big like glucose, it is LESS stable thus WEAKER intramolecular bonds, after combustion (or any other exothermic process) the enthalpy of the products is less than that of the reactions, where the products are MORE stable, with STRONGER bonds. Think complex is bad, and simple is good. Complex massive molecules are less stable ie. glucose for example, but CO2 and H2O are much more stable, with stronger bonds. For an endothermic reaction, energy is absorbed to make a less stable product of higher enthalpy, with weaker bonds as it is the reverse of an exothermic process.
3) In order to complete the circuit current needs to be carried by the soluble, mobile ions in the solution. The more complete the circuit is, or less problems required to obtain this flow with heaps of Na+ and Cl- (sorry I don't to physics, but..!) allows it all to happen much more efficiently as an electrolytic process. I'm not sure about the expression thing, hmm.
4) If something happens in VCAA that wasn't in a trial. Go with VCAA, you have to play by their rules ultimately. Do you remember which VCAA paper? I still have the 2011 and 2012s to go.
5) I think so, but that's a random guess that if there's more stuff there you get a higher voltage. Better get a physics nerd on this one!
1. I'm going to be nitpicky and say that sulfate can be oxidised in the reaction 2SO4 2- => S2O8 2- + 2e-
but you don't need to know that.
Also, please do NOT say that the electrodes have charges. THEY DO NOT! For starters, you could have a "positive" cathode in a galvanic cell. Besides, electrodes are electrically neutral. They have to be.
2. Complex is bad? Generally, yes, but not just due to bond strength reasons. Larger numbers of particles are associated with more disorder and entropy, which is thermodynamically favoured (just bear this in mind).
As for bond strengths, in the combustion of hydrogen, the H2 bond is actually very strong.
http://www.cem.msu.edu/~reusch/OrgPage/bndenrgy.htmH-H bond is almost as strong as the O-H bond due to the small size of the hydrogen atom. The oxygen molecule also has a strong bond; O=O IS a double bond. I suppose it's partly due to the stabilising effect of hydrogen bonding in water and of its polarity, coupled with the fact that oxygen atoms generally prefer to be in the oxidation state -2 due to their electronegativity.
But you can see why you need a spark to ignite hydrogen gas.
With combustion of organic compounds, think about the fact that C-C is also a relatively weaker bond.
3. Having an electrolyte increases the conductivity of the water, which allows charge to actually flow. Pure water's conductivity is tiny because it doesn't really have mobile charges in it, whereas if you have a dissolved salt, like sodium chloride, the charges present can stabilise any charge flow. If your charge can't move freely, your reaction is going to be slow.
Edward21 has basically covered everything, but just a few things to note:
3) Edward21 has basically said it, but note that, in general, the more ions there are in solution the more efficient the electrolysis is. so we want as many ions in solution as possible. the K value for the self-ionisation of water is, as you know, very low, whereas the Ksp value for the dissolution of solid NaCl is very high. so electrolysis of aqueous NaCl is much more efficient than electrolysis of water. but I don't do physics, so I'm not entirely sure what efficiency means in this context (NLIU!!), but the response above should suffice. also, normally we say electrolysis of electrolyte. I've yet to see a question which talks about the electrolysis of magnesium. it's usually "student X decided to electrolyse NaCl solution".
Be wary; if you have too much NaCl you can run into the chloralkali process.
4. I did that paper yesterday; VCAA 2011 Unit 4. In that case, we did have an equimolar reaction; the volume didn't matter.
5. Uh oh. Electrolyte concentration on cell voltage.
Do you mean generic sodium chloride electrolyte; the electrolyte which doesn't take part in the reaction?
If you mean something like AgOH, then of course concentration affects cell potential; increase the concentration of AgOH and the cell potential will increase. Increasing the concentration of the reactants will increase the cell potential and vice versa
If you mean a potassium nitrate electrolyte when electrolysing lead sulfate, for instance...I'm not too sure myself, but according to
http://www.lenntech.com/calculators/activity/activity-coefficient.htm, activity coefficients, which are a measure of how much a solution's properties deviate from ideal conditions, depend on the charge of the species involved, so I would presume if you were trying to reduce Sn 4+, this would be inhibited by a higher electrolyte concentration, even if the Sn 4+ concentration is constant.
Don't worry about this; first-year chemistry students don't worry about non-ideal solutions much either.
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