I'm hoping for an a*
But the only question I am confused on is the lead oxide one... All my friends say it's Pb4O3 and so does the Mark scheme but lookin through the internet and BBC bitsize I found out it's PbO

http://www.bbc.co.uk/scotland/learning/bitesize/standard/chemistry/calculations/calc_formulae_rev1.shtml

Exact same question just different masses.... Any suggestions anyone?!??

Element: Pb. O
Mass: 6.21. 0.64 (I think)

Rm: 207. 16
= 0.04 = 0.03
ratio: 1.3333. 1
Formula: PbO

...

If you looked at the second example question on that link it says "Step 6 is needed if any of the numbers in step 5 are not whole numbers". Therefore if you times 1.333333333 by 3 = 4 & 1 x 3= 3 so it is pb3o4 ( :

Reply 164

14dan2life

Original post by Altaf.khan96

I think thats 40? Probably an A

I thought the UMS marks were out of 100, not 50 for add science

Reply 165

west28

hey guys, any of you got a good prediciton of the grade boundaries? i reckon i got about 34 ( fingers crossed)

Reply 166

Mumzy

Original post by Altaf.khan96

Could you say hydrogen could come from Methane??

Yes, I wrote that too!

Reply 167

estudiante_numero1

Original post by west28

hey guys, any of you got a good prediciton of the grade boundaries? i reckon i got about 34 ( fingers crossed)

34 will almost certainly be 90 UMS. :smile:

Reply 168

estudiante_numero1

Original post by Altaf.khan96

Could you say hydrogen could come from Methane??

No, sorry, the correct answer was natural gas. Water may be permitted as acceptable in the 'allow' column. Sorry. :frown:

Reply 169

estudiante_numero1

Original post by 14dan2life

I've most likely got 36/45
Does anyone know what grade and UMS marks this will convert to?
Thanks x

36 will definitely be at least 90 UMS, possibly 95 UMS! :smile:

Reply 170

Altaf.khan96

Original post by 14dan2life

I thought the UMS marks were out of 100, not 50 for add science

Alright, you know when people say 34, do they mean 34/45 in marks? because it seems a bit low for A or is it just me? Lol it's my first year in additional :colondollar:

Reply 171

Aminaaa

This was such a nice paper! But the Grade Boundaries for Chemistry are always the highest :/

Reply 172

Rose.1994

Original post by Altaf.khan96

Alright, you know when people say 34, do they mean 34/45 in marks? because it seems a bit low for A or is it just me? Lol it's my first year in additional :colondollar:

yeah they mean marks,
in aqa additional science, the grade boundaries are always scaled down, its never 90% for A*

Reply 173

Rose.1994

Original post by 14dan2life

I thought the UMS marks were out of 100, not 50 for add science

yeah they're out of 100

Reply 174

hannahhhjayne

does anyone have a copy of the question paper, since i have forgotten some of the questions! thanks

Reply 175

07pbhambra

Original post by shewhomustnotbnamd

empirical formula one...and the one with the ship but that might have been c3

same i think the empirical formula is PbO?

Reply 176

07pbhambra

Original post by Rose.1994

cheers, have added them
can you remember the other questions?

u know for the activiation energy answer - could possibly kinetic energy be one answer option, since particles need to move and collide in order to react? and the empirical formula PbO?

Reply 177

Rose.1994

OFFICIAL GRADE BOUNDARIES:
A* - 32
A - 27
B - 21
C - 15
D - 12

Source: http://store.aqa.org.uk/over/stat_pdf/AQA-GCSE-UNIT-GDE-BOUND-JUNE11.PDF

Good luck for tomorrow everyone :smile:

Reply 178

Buongiorno