WJEC Chemistry Unit 3 2019

Dreadful!

It was harder than last year’s paper I thought... hoping for low boundaries. Any sign of an unofficial mark scheme or does anyone remember their answers to some of the maths questions? Would love to put my mind at rest knowing if I got any right!

Horrible exam, I practised so many Arrhenius equation questions and this one made no sense. And what the hell is huntite why are the WJEC obsessed with it. Where's my electrochemical cell diagram labelling!

I got something like 346K for temp?
but yeah horrible paper

Thought it got harder as I went through - better than when I did it last year but then perhaps resitting year 13 means I learnt more lol. Got a copy of the paper from my teacher today and the answers I get now are these ones - I'd say these are the ones I got in the exam but that's prob a lie - some seem familiar but others not.
Lattice energy question:Atomisation energy 121 (half the turning Cl2 into 2Cl)
Enthalpy of formation -2222 (I do remember getting that - a memorable number!)
Ionisation energy about 1200 - over half the energy to remove 2 electrons cos the ionisation energy for the second is bigger than the first
.Calcium chloride question 164 and x is 4
Arrhenius - after getting four different answers I got 346 twice in a row so I think that's right.
pH of ethanoic acid 3
Concentration of oxalis acid 0.16 mol dm-3
Huntite was just an empirical formula question using odd units so got a ratio of 1 Ca to 3 Mg so CaMg3 would need 4 carbonates to balance charge.
pH of dichromate I got 5.8. Looking at it now I can see that the bit about concentration of water being 55.5 is used here but didn't do that yesterday.
Got a C last year so fingers crossed for A at least this year.

what question was the pH of dichromate one?? i dont remember that and now i feel like i missed out a page or something

Right at the end it asked if a solution of equal amounts of chromate and dichromate was neutral and to do a calculation. The only calculation that made sense to me was to work out pH and show that it wasn't 7.

Right at the end it asked if a solution of equal amounts of chromate and dichromate was neutral and to do a calculation. The only calculation that made sense to me was to work out pH and show that it wasn't 7.

oh yh i remember that, that sounds like its right. here i am thinking i was smart by rearranging the Kc equation to find H+ and ended up getting an answer of pH 7.2 or something haha which is definitely wrong

Thought it got harder as I went through - better than when I did it last year but then perhaps resitting year 13 means I learnt more lol. Got a copy of the paper from my teacher today and the answers I get now are these ones - I'd say these are the ones I got in the exam but that's prob a lie - some seem familiar but others not.
Lattice energy question:Atomisation energy 121 (half the turning Cl2 into 2Cl)
Enthalpy of formation -2222 (I do remember getting that - a memorable number!)
Ionisation energy about 1200 - over half the energy to remove 2 electrons cos the ionisation energy for the second is bigger than the first
.Calcium chloride question 164 and x is 4
Arrhenius - after getting four different answers I got 346 twice in a row so I think that's right.
pH of ethanoic acid 3
Concentration of oxalis acid 0.16 mol dm-3
Huntite was just an empirical formula question using odd units so got a ratio of 1 Ca to 3 Mg so CaMg3 would need 4 carbonates to balance charge.
pH of dichromate I got 5.8. Looking at it now I can see that the bit about concentration of water being 55.5 is used here but didn't do that yesterday.
Got a C last year so fingers crossed for A at least this year.

4 carbonates to balance charge? I thought it only asked for the empirical formula. Did I miss a page or something???
I think I misread the question ugh