IGCSE/GCSE/O & A Level/IB/University Student Forum
Qualification => Subject Doubts => IGCSE/ GCSE => Sciences => Topic started by: Naruto on June 07, 2009, 03:01:10 pm
-
hey
When i was going through the papers i didn't got the answer for the following questions and i guess the answers that i have are wrong so can anyone tell me the answer and explian it too. Thanks :)
The answers that i have are:
16 is D
19 is C
39 is B
If you think these answers are correct then plzz explain and if not then what is the right answer? and again explain :P
I have attached the questions
-
16 i aint sure of but i say its
B
19 is definatly B as it contains an iodide which turns yellow.
39 is C as the number of molecules havent changed.. 2 carbons which weigh 12 and 4 hydrogens = Mr of 28
and the same thing for polyethene the Mr hasnt changed.
-
16 i aint sure of but i say its
B
19 is definatly B as it contains an iodide which turns yellow.
39 is C as the number of molecules havent changed.. 2 carbons which weigh 12 and 4 hydrogens = Mr of 28
and the same thing for polyethene the Mr hasnt changed.
please dont answer if ur not sure of ur answers.....16 is D
19 is B
39 is B.....100 percent sure
-
19 is B 39 is B
and as for the 16 part my guess is that it isC
It cant be D because the time has started but the reaction hasnt..
it cant be A because th reaction has to slow down to come on an end
it cant be B because the speed of reaction is greatest when the aprticles have most energy/concentration..
so it is C (i guess)
+ rep if u like it
bcoz already mine is in minuses
-
nope.
16 is b
19 b
39 b
without doubts
-
nope.
16 is b
19 b
39 b
without doubts
can u plz explain ur answers to 16 and 39
Thanks..
-
are u guys talking about chem p1 09 june or some other
if u are i would like to tell u plz dont leak answers
-
are u guys talking about chem p1 09 june or some other
if u are i would like to tell u plz dont leak answers
ooyyeee....these r past pprs ques...v hv doubt in it...
no one has don't chem p1 newhere in the world...its on 10th for everybody...
so plz if u cn explain id aapreciate...Thanks..
-
16 is d for sure ,because during explosions very strong heat is released immediately and not gradually . so it increase and after explosions it decreases again
-
guys.. how the hell is 39 B..
its C for sure..
how the hell can u even get an empirical formula without knowing the % and stuff..
molecular formula is the same..
c 12 and c 12 make 24
h-h-h-h= 4
24+4 = 28..
the same with polyethene!
-
ok well first 19 should be K2SO4 as yellow ppt produce by sulphur.
16 according to me should be B as first the explosion reaction will cause inc. in rate of RX but then reaction will stabilise but continue at a certain speed.this can be seen in nuclear reactors too and thats why boron rods are put to regulate the speed of reaction.39 i think should be B as no matter what happens there will be 2 atoms of c and 4 atoms of h in 'n' number of molecules too.hope this helps.
-
19 is B
39 is B
16 is D(after a lot of research on explosion and reaction rate)
-
i think the 39 answer is B
In an addition polymerisation unsaturated monomer units react together to form a polymer with essentially the same empirical formula as the monomer
-
for the 16th one i think its (b)
-
16 = C
19 = B
39 = B
-
for the 16th one i think its (b)
no adi it's D for sure. It's an explosive reaction..i have done lot of research. and for 39 i earlier posted C because i thought C was empirical so sorry abt that
-
16 = C
19 = B
39 = B
three answers confused,,,!!!
hey and i chked out in docbrown
they say that the speed of reaction in this experiment increases with time...but later slows down
are u sure??
and yaa its the empirical thingy..no problemm...!!
-
16 = C
19 = B
39 = B
three answers confused,,,!!!
hey and i chked out in docbrown
they say that the speed of reaction in this experiment increases with time...but later slows down
are u sure??
and yaa its the empirical thingy..no problemm...!!
they r normal reactions..the combustion of hydrogen is an explosive reaction...and so this is what happens..i'm 100% sure...i read one whole chapter of a book on explosive combustion reaction rates
-
okk..no problem..
thanks
where r the others..
no ones coming in to help others
all r busy in the chit-chat thrad
all busy loving sum1 :-X
-
:-X
take back ur words
haha..kidding
-
:-X
take back ur words
haha..kidding
u better be .....lol
-
19 is B
39 is B
16 is D(after a lot of research on explosion and reaction rate)
yah thats correct....
-
Quick question: in 16, why does the hydrogen not start to react until a while into the experiment?
-
Which year? 08?
-
Which year? 08?
hey ur back
nice ta see ya again
-
Thank you kam really appreciate it
-
Quick question: in 16, why does the hydrogen not start to react until a while into the experiment?
hydrogen does not react instantly...it requires to initiated(even thought the reaction is exothermic)..There's something known as an activation energy that it requires...and so does not react instantly. But once it starts reacting, the reaction produces immense heat, which is more than the optimum energy for the reaction...remember that the reaction is exothermic so very high temperatures do not favour the reaction and the yield of the product decreases with time.
-
just wondering if any1 has the mark schemes to the paper 1 chemistry for d old papers..........
can u pls send them...
-
here https://studentforums.biz/index.php/topic,2342.60.html and https://studentforums.biz/index.php/topic,2342.45.html
+rep hmh cuz he put it up
-
here https://studentforums.biz/index.php/topic,2342.60.html and https://studentforums.biz/index.php/topic,2342.45.html
+rep hmh cuz he put it up
the ones that he put up are for physics....
i was wondering if u had the chem ones.... :)
-
oopsy im sorry but ill look for u
-
hi there.i need mark schemes for chemistry paper1 from 2000 to 2003 ,can anybody help???
-
Hi..Chemistry mark schemes are available from Nov01-Nov08 on www.freeexampapers.com
But for 2000 and Jun01 I'll look them up for you
-
oopsy im sorry but ill look for u
Thanks....
+ rep..... :)
-
hey
i have attached the questions that i dint understood...plzzz telll me the answer so that i can check that whether the answer that i have are right or wrong :-\ and plzzz try to explain your answers thanks
-
hey
i have attached the questions that i dint understood...plzzz telll me the answer so that i can check that whether the answer that i have are right or wrong :-\ and plzzz try to explain your answers thanks
where r the questions ??
-
May 1998 paper 1 q no.4 can u pls confirm answer .
as per me it shld be "C" but is "D" as per ms.
-
its c man,,,there is a mistake for sure in dat ms....
why would u need a clock .\\\\\>>>
-
Thanks
-
Any one has marking schemes for paper1 chemistry from 1999 till 2002???
I can't find them any where ,,, please help!!!
-
Any one has marking schemes for paper1 chemistry from 1999 till 2002???
I can't find them any where ,,, please help!!!
dont have it on my computer..only have the answer book...
-
i hv form 1994-2003
need ;em
email me
ill send them to u
my id unevaknw@windowslive.com
-
can u put them up on a file sharing site..like zshare or on skydrive
-
sky drive is better
-
ok now i have attached the question so plzz check them above...
thank U :)
-
hey
i have attached the questions that i dint understood...plzzz telll me the answer so that i can check that whether the answer that i have are right or wrong :-\ and plzzz try to explain your answers thanks
25 is A. Magnesium is more reactive than carbon..carbon cannot reduce magnesium from its oxide. So the mixture remains black and there's no change in limewater
37 is A. Both can be used as fuels
39 is D. Just add the products' molecular formula. CH4 and 2 molecules of C2H4 will give C5H12
-
ok now i have attached the question so plzz check them above...
thank U :)
all A
last one is D
-
hey
i have attached the questions that i dint understood...plzzz telll me the answer so that i can check that whether the answer that i have are right or wrong :-\ and plzzz try to explain your answers thanks
okk no idea abt the 37th one
but the rest 2
q25.) i think its A...because Magnesium oxide cannot be reduced
q38.) ans - "D" -- C5H12 ==> C2H4 + C2H4 + CH4
-
its written 2 molecules of ethene so wont it be "D"
-
@ Yu Si-hun: Delete the sites right away or u will be banned
-
THIS IS IGCSE CHEM?
if not WHY is it in the IGCSE thread.. can u plz move it?
-
@ Yu Si-hun: Delete the sites right away or u will be banned
i strongly feel u shud delete this sites..
u r so surely gonna be banned...
nid..please check my answer posted above
thank u
-
we can read- dont have to space it out ???
-
hey
i have attached the questions that i dint understood...plzzz telll me the answer so that i can check that whether the answer that i have are right or wrong :-\ and plzzz try to explain your answers thanks
okk no idea abt the 37th one
but the rest 2
q25.) i think its A...because Magnesium oxide cannot be reduced
q38.) ans - "D" -- C5H12 ==> C2H4 + C2H4 + CH4
yes naruto it's D for 38..my bad. I didn't see there were two molecules of ethene
-
thank u..
-
pls delete that post christy...ull have to delete it anyway cuz it's got the sites in it
-
sorry ..... :D ... was kinda fustrated at the link :P
-
its deleted
a quick reaction by the admin
-
Once again, please no cheating.
Thanks
-
its deleted
a quick reaction by the admin
hehe ... she told me to delete it so i deleted it ... no admin did tht :P
-
lol,,
i am talkin abt the sites posted by yu-shin (don't remember his name)
-
hehe .... ok :) sorry then
-
Thanks guyz for answering the answers that i have are:
25 is A
37 is A
39 is A
but even i think that 39 is D and i guess the marksheme is wrong
Anywayz which site are you talking about ??? plzzzzzzzzzzzz tell me ;)
-
which year are you guys talking about?