Ocr f321 23 may 2013~official discussion thread

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Ferrari_1996

yh multiplying number of moles by avagadro's constant should give you number of molecules. If you then multiplied THAT number by the number of atoms in the SiCl4 molecule (i.e. 5) then that would give you number of atoms. But it sounds like you got it right nyway.

Yeah I got it right :smile:

Reply 1221

Funtry

Original post by JoshBridgett

Thanks for clearing this up.. I was wondering this myself :smile:

I ended up with the number of moles, should only lose 1 mark since Avagadro's Constant is given in the formula booklet?

I'd say 1 mimimum, 2 maximum (depending on your answer for moles). You should definitely get an M1 mark, maybe an A1 mark too if you're lucky. (one M1 mark for timesing by AC and maybe the A1 mark for the number of molecules, maybe it's for the number of moles, depends on how the mark scheme is.)

Reply 1222

gaby_xo

I screwed up really badly on on the group 2 chloride question:-(
Stress of being in isolation because I had 3 exams today made me so nervous that I took way too long on the first half and rushed the second half.
Anyone know what the question about across period 2 was?
I remember there was three big questions.. On on ionisation , another one was a chloride and another one was abound bonding and structure?
Or am I getting confused

Reply 1223

JoshBridgett

Original post by Funtry

Ah ok thanks, I had 0.05 for the number of moles, I knew something was missing but I thought that Avagadro's constant was just number of atoms. Hopefully the mark scheme is generous :smile:

Reply 1224

scorpio22

Original post by Nermin Hayek

It's definitely 360 because it was multiplying the mole ratio by 3 not the final volume

thanks. the last question on particles and bonding column was wishy washy I thought . I missed out drawing my other 6 elections on the 3 fllourines in nh3bf3.. after I everything else right. I only get one Mark.I didn't even see the k+ on first q

Reply 1225

Ferrari_1996

Original post by Stiffmeister

Will you get ecf for the dipole-dipole question.
Its 1080cm3

I remember getting 360cm3 for a question. I think you got 360 and multiplied it by 3 but I think you had to multiply by 3 before, not in the end. I hope someone can clarify this.

Reply 1226

Nermin Hayek

Original post by scorpio22

I forgot to draw them too
lost out on 6 kinda silly marks ... Hoping I can still get an A

Reply 1227

Liberty.

Well I hope it's 360, since I've already lost at least 10 marks on stupid mistakes don't need any more :cry:

Reply 1228

gogo122

I felt really confident after doing the paper but now im starting to feel like i've lost about 15 marks :frown:

. Btw on the drawing the ionic kcl question, I forgot to put the charges on the K+ and cl-, how many marks will I lose on that question?

Reply 1229

jackitsme

Original post by Nermin Hayek

I forgot to draw them too
lost out on 6 kinda silly marks ... Hoping I can still get an A

you get the mark despite not drawing the six other electrons it only ask to show for paired in markschemes

if it were ionic you would have to show all

Reply 1230

Nutter95

I made loads of stupid mistakes on this exam. Didn't realise until I came out of the exam hall. :unimpressed:

Reply 1231

jackitsme

Original post by gaby_xo

there was no bonding and structure,many failed to read it was about IE of the LI,C and F

so its about shells ect

Reply 1232

Nermin Hayek

Original post by jackitsme

you get the mark despite not drawing the six other electrons it only ask to show for paired in markschemes

if it were ionic you would have to show all

Oh really ? even if they asked us to show outer shell electrons? That's a relief :smile:

Reply 1233

Liberty.

Original post by gogo122

I felt really confident after doing the paper but now im starting to feel like i've lost about 15 marks :frown:

. Btw on the drawing the ionic kcl question, I forgot to put the charges on the K+ and cl-, how many marks will I lose on that question?

Ugh, same

It was out of 2, so we should probably get 1.

Reply 1234

Geronimo!

Original post by Funtry

Incorrect, unless it was asking for the number of atoms (which is wasn't I don't think). A mole doesn't always apply to atoms (see previous post).

how many marks would i get from that?? :frown:

Reply 1235

jackitsme

Original post by Nermin Hayek

Oh really? That's a relief :smile:

yup because its a full shell so no point showing the rest,BOTD(benifit of the doubt woud be given)

Reply 1236

Char-

OH MY GOSH! IT'S OVER.

Thats the 3rd time i've taken that exam, for the love of god, I am never doing it again.
Does anyone have an unofficial mark scheme floating around?

Plus what did you get on the water of crystallisation question?

Hope it all went well for youuuu!!!!!!