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I did it a bit differently and got the correct answer as well.
72/24000 = 0.003 moles of carbon dioxide.
mass of carbon = 0.003 * 12 = 0.0036g.
0.144 - 0.0036 = 0.108 g of X (Aluminium) left.
0.108/27 = 0.004 of Aluminium
Ratio of Al to C
0.004 : 0.003
4 : 3
therefore it is Al4C3
Somebody please reply fast.. i have 2 hours left. Im done with all the papers back till 2002. Ive gone through my notes once. what should i do right now?? chemguide or the book (coursebook by David Acaster) plz note that I have 2 hours only and went through each looong way back
Hey umm im confused in question number 30 why do we use the moles of the ACID not alcohol? :/ and can anyone pleaase explain me questions number 4, 5 and 12 in the same exam? Thank uQ 30!
okay here goes, so you know when we find the yield in an ester rxn we use the acid right?
so the mass of the ethanoic acid given is 30, which divided by the mr of the acid
30/60 = 0.5 moles
and in the end the ester formed has mass 22g while its mr is 88, moles of ester formed,
22/88 = 0.25 moles
so if 0.5 moles of acid produces o.25 moles of the ester, we have
(0.25/0.5) x 100 = 50%
hope you got it, dnt mind asking if u didnt.
i'll just do 39 and post it up in a bit
q31 answer is C ? :SCan somebody explain those?
View attachment 28900
q23 - What do they mean by mole fraction is 0.5? How does that affect the identity of X?
View attachment 28901
q33 - Why is it 1? Why isn't it 2?
View attachment 28902
q35 -How does nitrogen undergo a redox reaction? It only goes from +3 to 0.
View attachment 28904
q31 - Where do ionic bonds form? All elements present are non metals?
umm its not an option.. i asked my teacher the samething, he said that we have to think of the acid as a limiting agent..Hey umm im confused in question number 30 why do we use the moles of the ACID not alcohol? :/ and can anyone pleaase explain me questions number 4, 5 and 12 in the same exam? Thank u
q31 answer is C ? :S
add all the electrons..Hey umm im confused in question number 30 why do we use the moles of the ACID not alcohol? :/ and can anyone pleaase explain me questions number 4, 5 and 12 in the same exam? Thank u
Q5Hey umm im confused in question number 30 why do we use the moles of the ACID not alcohol? :/ and can anyone pleaase explain me questions number 4, 5 and 12 in the same exam? Thank u
Can somebody explain those?
View attachment 28900
q23 - What do they mean by mole fraction is 0.5? How does that affect the identity of X?
View attachment 28901
q33 - Why is it 1? Why isn't it 2?
View attachment 28902
q35 -How does nitrogen undergo a redox reaction? It only goes from +3 to 0.
View attachment 28904
q31 - Where do ionic bonds form? All elements present are non metals?
http://papers.xtremepapers.com/CIE/...d AS Level/Chemistry (9701)/9701_s07_qp_1.pdf Q9 plz :/Nope it's B.
Sulfur trioxide is acidic, and ammonia is a base so that's an acid-base reaction. If you check the equation no oxidation or reduction takes place in any of the elements.
Its C aluminum carbide
Al4C3+12H2O------->4AL(OH)3+3CH4
CH4+2O2----->2H2O+CO2
Moles of CO2=72/24000=0.003
moles of Al4C3= 0.003/3=0.001 (as ratio of Al4C3:CH4 is 1:3)
now mass of Al4C3= 0.001 into (27+27+27+27+12+12+12)=0.144g
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dis was done by jiyad ahsan
what about question 34 in may june 07? ThanksQ5
the answer is D, since when the difference between molecules of a liquid and a gas is the forces holding the liquid molecules together so, in this case hydrogen bonding
so just vaporize a mole of liquid hydrogen halide and note down the energy change that would also be an indicator to the strength of the (hydrogen)bonds
Can somebody explain those?
View attachment 28900
q23 - What do they mean by mole fraction is 0.5? How does that affect the identity of X?
View attachment 28901
q33 - Why is it 1? Why isn't it 2?
View attachment 28902
q35 -How does nitrogen undergo a redox reaction? It only goes from +3 to 0.
View attachment 28904
q31 - Where do ionic bonds form? All elements present are non metals?
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