Chemistry: Post your doubts here!

[ashcull14]

 

[unique111]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s13_qp_13.pdf
Q.28 C
Q.29 D
Q.30 C

Somebody, help with these too?

 

[IGCSE13]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s13_qp_11.pdf Q11 ansB Q20 ansB Q30 ansB

 

[ashcull14]

full explanation plx..step by step

 

[huh]

I regret not studying chemistry hard enough. Please help!!
http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_w12_qp_11.pdf

Q11.

 

[papajohn]

Q28 C how??
http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s13_qp_13.pdf

 

[ashcull14]

 

[kitkat <3 :P]

http://papers.xtremepapers.com/CIE/... AS Level/Chemistry (9701)/9701_s10_qp_12.pdf
Q12 anyone :'/

 

[zem]

Need help

 

[_Ahmad]

Can someone plz plz plz answer this question...

1) is correct because nitrogen is reducing and chlorine is oxidizing so nitrogen undergoes a redox reaction
2) NaClO is the bleach
3) AgNO3 (aqueous) + NaCl (aqueous) -----> AgCl (white precipitate) + NaNO3 (aqueous)

therefore answer = A

 

[Snowysangel]

View attachment 45114

D

 

[SIstudy]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_s12_qp_11.pdf
Q23 ?? :/ (ANS - B)
I don't really get the compound C drawn :S

 

[Snowysangel]

Need helpView attachment 45119

3%

 

[Snowysangel]

View attachment 45118

Is it A?

 

[Youssef Tawil]

There has to be a attachment to 2 ADJACENT carbons which is C

 

[Snowysangel]

View attachment 45117
full explanation plx..step by step

C

 

[ashcull14]

ex

D

can u explain all the 3 ques plx

 

[Suchal Riaz]

who i n helll will think to do this correct only 1 mark omg jesus christ the merciful

it takes no more than 1 minute. and you have 1.5 minutes to do each question.

 

[Suchal Riaz]

why isn't the number of moles of H2 taken into account? why only N2? :/ :S

you could do that with H2 too.
number of moles of H2 used : number of moles of NH3 = 3:2
so (60 000 - 48 000):x=3:2
X=12 000*2/3=8000 moles = 136 Kg

 

[_Ahmad]

Need helpView attachment 45119

2 NaHCO3 + H2SO4 → 2 CO2(g) + 2H2O(l) + Na2SO4

n(H2SO4)=(7.15*10^-3)*0.1=0.715*10^-3 mol

using mole ratio n(NaHCO3)=2*n(H2SO4)=2*(0.715*10^-3)=1.43*10^-3 mol

since you have got n(NaHCO3) you can find mass of NaHCO3 reacted = n*(mr of NaHCO3)=0.1202g

%by mass of NaHCO3 =(0.1202/1)*100=12.012~12.0%

therefore answer =C