this is a spoof, kidding xD
wanna know who here take pure. chem also
it was easy =.=
the most difficult is like
the co2 nvr get into atmosphere nia =.=
paper okay..i forgot need to calculate no. of moles in qn 7 all the way lol
i dunno how hydrogen fuel produce electrical energy also
wikianswers say ethanol produce carbon dioxide which i dunno why.
http://wiki.answers.com/Q/Is_ethanol_carbon_neutral_or_not
i say produce co2 then dissolve in water become acid, thats why bo co2 escape.
haha produce electricity cause the h2 react with oh- to form h2o and 4e-
therefore gen electricity due to electron .
tb - energy changes have fuel cell. =)
Pure chem really easy ah? ( in overall)
yaya
but it was more difficult then last year O lv. =)
all i know ish what is pure chem ar?
But then why can't all school open double science leh ):
Originally posted by tr@nsp0rt_F3V3R:all i know ish what is pure chem ar?
Pure Chemistry = 1 subject in the O lvl
the carbon neutral that question is about carbon cycle, refer to textbook i think pg 374
CO2 dissolve is wrong. i got that Qn wrong too. zzz.
Originally posted by ƒlame:Pure Chemistry = 1 subject in the O lvl
i think he meant the paper was uber easy?
Originally posted by forum-er93:CO2 dissolve is wrong. i got that Qn wrong too. zzz.
that question was given very little emphasis by teacher, but it came out lols
1 hour before the paper began, I was being taught by a friend the entire chunk of organic chemistry. Yes, taught, not tutored.
Before that, I never knew what the hell an alkane or alkene was.
Considering that organic chemistry was fresh in my head and that 1/3 of the paper was related to the organic chemistry, I found the paper relatively easy.
I think overall I'll definitely get above 60/80 or 75% for paper 2.
Hardest questions were probably the hydrogen fuel cell one, or the question on why ethanol isn't a carbon pollutant (related to photosynthesis according to my teacher) or something like that.
Do note that considering the toughness of the paper, I think A1 for chemistry overall might be slightly above 85%.
i think a1 might even be above 90%. many only minused 3-5 marks in my school. everyone did well!
90%?!! Omg!
My friend check internet found out that plants take in carbon dioxide to form sugar. Although ethanol from the sugar produces carbon dioxide, there is no carbon dioxide being produced overall.
just a guess. =)
it really was easy except for a few uncommon ones.
Well, the national distinction rate for all the subjects last year was really high.
Maybe it's just that 2008 and 2009 O' Level papers are the new syllabus and ridiculously easy.
Anyways, I remember that I was always complaining to my friends on why I didn't drop to combine science for a "free A1".
Now I'm quite satisfied with staying in pure science after seeing the chemistry paper.
manageable
not much qns that is tricky
do either
or was quite easy too, electrolysis lol
wana confirm, so whats the answer for the carbon neutral ? X.X
my intepretion of the qn is why u combust ethanol ( fuel what) will not result in co2 escaping.
hence i say dissolve in water to form acid >_>
sugar is produced by plant in photosynthesize, take in CO2, when burn release back CO2 to atmosphere, Carbon neutral lah
plant take in CO2 to form sugar
CO2 released in fermentation
CO2 released in combustion.
so many release. how neutral?
ok la, makes sense actually
sugar is produced by plant in photosynthesize, take in CO2, when burn release back CO2 to atmosphere, Carbon neutral lah
~.~
Equation for photosynthesize
(over simplified)
6CO2 + 12 H20 -- chlorophyll / light energy --> 6 H20 +C6H12O6 + 6 CO2
C6H12O6 --> 2 C2H5OH + 2 CO2
2C2H5OH + 7O2 --> 4 CO2 + 6H20
thus total CO2 take in 6 unit, give out 6 unit
understand !
then the electriciity 1 is wadddd~