Chemistry Help HERE ONLY !!

[Hope]

thank you so much sanity_master and godfather!!  
highly appreciated (a)

[godfather93]

i sent it as well! oh well!

[sanity_master]

lol......no harm with that lol

[Hope]

By the way..gave you both +reps

[sanity_master]

Thanks....hope they r useful

[frenzy1234]

dunno if this is the right place but anywas ...
ive done past papers from 2003-2008 for chem pp3
and i dnt have any more papers nor are any papers avalible online cn sm1 help me on how i shld practise now??

[asus]

can anyone here help me with the oxidant and reductant...??..
like in ppr3 june 06...question 6 ( c )...

[godfather93]

the reductant is zinc and the oxidant is hydrogen

[asus]

the reductant is zinc and the oxidant is hydrogen

thanks..but could u explain it?..
 

[godfather93]

first of all the definitions of reductant and oxidant are
reductant - causes the other element to be reduced. when this happens the reductant is oxidised (loses electrons)
oxidant - cause the other element to be oxidised. when this happens the oxidant is reduced (gains electrons)

zinc is the reductant because it is being oxidised. the metal is being transformed into ions and electrons are given out (hence the zinc rod becomes thinner)
hydrogen is the oxidant because the hydrogen ions in the electrolyte is being changed into hydrogen gas(hydrogen is being reduced)

[asus]

first of all the definitions of reductant and oxidant are
reductant - causes the other element to be reduced. when this happens the reductant is oxidised (loses electrons)
oxidant - cause the other element to be oxidised. when this happens the oxidant is reduced (gains electrons)

zinc is the reductant because it is being oxidised. the metal is being transformed into ions and electrons are given out (hence the zinc rod becomes thinner)
hydrogen is the oxidant because the hydrogen ions in the electrolyte is being changed into hydrogen gas(hydrogen is being reduced)

i think i got it...
million thanks to u..

[godfather93]

welcome all the way!

[MaNa]

I need help in chemistry  oct/nov 08 second varient paper
Q 7ai)

[Roza]

I need help in chemistry  oct/nov 08 second varient paper
Q 7ai)

i actually got this question for my mocks

here's the working
volume of oxygen left
according to question             according to equation
1 mol                                         6.5 mol
if 20cm3                                           x??
so 20 x 6.5 = 130cm3

150-130 = 20cm3

so volume of oxygen left = 20cm3

volume of carbondioxide formed

1                       4
20                     x??
so 20 x 4 = 80

volume of carbondioxide formed = 80cm3

[MaNa]

I need help in chemistry  oct/nov 08 second varient paper
Q 7ai)

i actually got this question for my mocks

here's the working
volume of oxygen left
according to question             according to equation
1 mol                                         6.5 mol
if 20cm3                                           x??
so 20 x 6.5 = 130cm3

150-130 = 20cm3

so volume of oxygen left = 20cm3

volume of carbondioxide formed

1                       4
20                     x??
so 20 x 4 = 80

volume of carbondioxide formed = 80cm3

Thankyou but wont we use the formulaa???
n umm why did u subtracted it form 150?