Chemistry: Post your doubts here!

[_Ahmad]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w11_qp_11.pdf

Q4(C),17(C),20(C),27(D),35(B),36(A)

 

[Metanoia]

To wat time r u available today,sir

Its nearly 9pm here. I think at most i would stay is till 11pm. Even so, i would only check in occasionally instead of staring at the CPU throughout.

It there are too many questions, I might only focus on those that were not answered before, cause some questions are repeated, students can find them answered by doing a search.

 

[Suchal Riaz]

Suchal Riaz R u still angrey ??!!

i had to listen to eminem for 15 minutes to calm down.

 

[ZaqZainab]

can anyone how to solve ques 12 View attachment 45157

Initial 1 1 0 0
change -x -x +x +x
Final 1-x 1-x x x
so Kc x^2/(1-x)^2 =4
make x the subject

 

[Suchal Riaz]

can anyone how to solve ques 12 View attachment 45157

ZaqZainab this is how to solve

 

[♣♠ Magnanimous ♣♠]

ZaqZainab this is how to solve

well bro why did you take values of water and ethyl ethanoate as 1?

 

[♣♠ Magnanimous ♣♠]

Initial 1 1 0
change -x -x +x
Final 1-x 1-x x
so Kc x/(1-x)^2 =4
make x the subject

well do it for me please... coz i am weak at maths so Thought blocker isn't it?

 

[ZaqZainab]

ZaqZainab this is how to solve

I didn't use paint i did the same way too

 

[Thought blocker]

well do it for me please... coz i am weak at maths so Thought blocker isn't it?

?

 

[ZaqZainab]

well do it for me please... coz i am weak at maths so Thought blocker isn't it?

see suchal did it

 

[♣♠ Magnanimous ♣♠]

can you say how to solve ques 3?

 

[♣♠ Magnanimous ♣♠]

see suchal did it

but why did he take water and that other product value as 1?

 

[Suchal Riaz]

well bro why did you take values of water and ethyl ethanoate as 1?

questions says that there are one mole of water and ethyl ethanoate.
and when Kc has no units or when the volume of concentration cancel out, moles can be used in the equation.
[a]/[c][d] = (n(a)n(b)/V)/(n(c)n(d)/V) volume will cancel out giving number of moles only.

 

[♣♠ Magnanimous ♣♠]

questions says that there are one mole of water and ethyl ethanoate.
and when Kc has no units or when the volume of concentration cancel out, moles can be used in the equation.
[a]/[c][d] = (n(a)n(b)/V)/(n(c)n(d)/V) volume will cancel out giving number of moles only.

ok thanks dude

 

[ZaqZainab]

questions says that there are one mole of water and ethyl ethanoate.
and when Kc has no units or when the volume of concentration cancel out, moles can be used in the equation.
[a]/[c][d] = (n(a)n(b)/V)/(n(c)n(d)/V) volume will cancel out giving number of moles only.

In the question it doesnt say one mole of water

 

[IGCSE13]

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

 

[Suchal Riaz]

 

[princessnoor]

t

In statement 1, 2 moles of ethanoic acid will react with 1 mole of calcium ion as charge on calcium is +2. So compound will be Ca(CH3CO2)2 which has empirical formula CaC4H6O4.
In 2 and 3, both H from CO2H will be removed so empirical formula will be CaC4H4O4 and not CaC4H6O4.

thanku

 

[_Ahmad]

http://papers.xtremepapers.com/CIE/Cambridge International A and AS Level/Chemistry (9701)/9701_w11_qp_11.pdf

Q4(C),17(C),20(C),27(D),35(B),36(A)

 

[Suchal Riaz]

i meant moles of ethanol and ethanoic acid

In the question it doesnt say one mole of water