Alex1307 Posted May 12, 2011 Report Share Posted May 12, 2011 I remember there was a question about how to test for alkane or alkene...don't exactly remember but what did you guys write??Bromine water! If it's an alkene, then the water will decolorize (due to the addition reaction of Br2 to alkene to form dibromoalkane).If it's an alkane, then nothing happens and the bromine water remains red/orange.i put the other way around It's okay you're still getting one mark for writing bromine water Reply Link to post Share on other sites More sharing options...
mehann Posted May 12, 2011 Report Share Posted May 12, 2011 what is the percentage error for the question 1, section A?n the ph for ques 5 section B? Reply Link to post Share on other sites More sharing options...
Alex1307 Posted May 12, 2011 Report Share Posted May 12, 2011 what is the percentage error for the question 1, section A?n the ph for ques 5 section B?Using 70 kJ/mol, the percentage error was something like 10-11%And I have no idea for question 5. Sorry Reply Link to post Share on other sites More sharing options...
mehann Posted May 12, 2011 Report Share Posted May 12, 2011 i got around 40%-50% omg that carries a lot of mark Reply Link to post Share on other sites More sharing options...
Alex1307 Posted May 12, 2011 Report Share Posted May 12, 2011 i got around 40%-50% omg that carries a lot of mark I'm not 100% sure though!What value did you find for the enthalpy in question 1? Maybe your enthalpy wasn't right? Reply Link to post Share on other sites More sharing options...
mehann Posted May 12, 2011 Report Share Posted May 12, 2011 40 something.. couldnt rmmber.. the new format (boxes) is really disturbing~! it's difficult to read all ques in section B n to decide which ques u can answer correct the most.. i end up chosing no 5.. i never answered acid n base ques before.. Reply Link to post Share on other sites More sharing options...
Alex1307 Posted May 12, 2011 Report Share Posted May 12, 2011 40 something.. couldnt rmmber.. the new format (boxes) is really disturbing~! it's difficult to read all ques in section B n to decide which ques u can answer correct the most.. i end up chosing no 5.. i never answered acid n base ques before..I know right! I hated theses boxes. All of my answer/calculation went outside the boxes and I had 12678 extra answer sheet Reply Link to post Share on other sites More sharing options...
suggaplum Posted May 13, 2011 Author Report Share Posted May 13, 2011 40 something.. couldnt rmmber.. the new format (boxes) is really disturbing~! it's difficult to read all ques in section B n to decide which ques u can answer correct the most.. i end up chosing no 5.. i never answered acid n base ques before..I know right! I hated theses boxes. All of my answer/calculation went outside the boxes and I had 12678 extra answer sheet On the contrary, I thought they were reasonable sized. They basically tell me how much I would have to write. However I do agree the fact that it requires more time and effort to choose questions since the questions are not all on one page.. Reply Link to post Share on other sites More sharing options...
gkong Posted May 14, 2011 Report Share Posted May 14, 2011 40 something.. couldnt rmmber.. the new format (boxes) is really disturbing~! it's difficult to read all ques in section B n to decide which ques u can answer correct the most.. i end up chosing no 5.. i never answered acid n base ques before..I know right! I hated theses boxes. All of my answer/calculation went outside the boxes and I had 12678 extra answer sheet On the contrary, I thought they were reasonable sized. They basically tell me how much I would have to write. However I do agree the fact that it requires more time and effort to choose questions since the questions are not all on one page..I didn't know for the graph you had to account for heat loss just because when we do our calorimetry lab the temperature doesn't drop dramatically. However I got Mid 30s for percentage error anyway. ECF!!!! Reply Link to post Share on other sites More sharing options...
suggaplum Posted May 14, 2011 Author Report Share Posted May 14, 2011 40 something.. couldnt rmmber.. the new format (boxes) is really disturbing~! it's difficult to read all ques in section B n to decide which ques u can answer correct the most.. i end up chosing no 5.. i never answered acid n base ques before..I know right! I hated theses boxes. All of my answer/calculation went outside the boxes and I had 12678 extra answer sheet On the contrary, I thought they were reasonable sized. They basically tell me how much I would have to write. However I do agree the fact that it requires more time and effort to choose questions since the questions are not all on one page..I didn't know for the graph you had to account for heat loss just because when we do our calorimetry lab the temperature doesn't drop dramatically. However I got Mid 30s for percentage error anyway. ECF!!!!The question did state however, if no heat is loss throughout the process, calculate the temperature change. But to be honest, that question was awfully odd, and I swear ECF would definitely help me.. Reply Link to post Share on other sites More sharing options...
lighthuntz0r Posted May 14, 2011 Report Share Posted May 14, 2011 (edited) You have to extrapolate for heat loss AFAIK. My error was low, something like 3 or 5%, don't remember correctly. Edited May 14, 2011 by lighthuntz0r Reply Link to post Share on other sites More sharing options...
alicjar Posted May 15, 2011 Report Share Posted May 15, 2011 yeah I also screwed up first question in section A paper 2... anyway, do you think they will really give us some points if the method was right, but the calculations were stupid, i mean i didn't add the amount of water, that is why the enthalpy change was so low eventually Reply Link to post Share on other sites More sharing options...
AvifromtheOC Posted May 16, 2011 Report Share Posted May 16, 2011 In the aufbau principle one, I put all arrows up.As for the Kc question, I calculated the equilibrium concentrations using the x method and I think it turned out to be right. TO be honest, this wasn't a very difficult paper except for QUESTION 1 which was just a messed up question. paper 1 though was tricky. Really don't know what I'll get there! Reply Link to post Share on other sites More sharing options...
suggaplum Posted May 17, 2011 Author Report Share Posted May 17, 2011 For multiple choice, what did everyone get for the last question on significant numbers? I thought that was a very odd question since i was expecting something on accuracy/precision Reply Link to post Share on other sites More sharing options...
Alex1307 Posted May 17, 2011 Report Share Posted May 17, 2011 For multiple choice, what did everyone get for the last question on significant numbers? I thought that was a very odd question since i was expecting something on accuracy/precisionHmmm I think my answer had something like 5 significant numbers? But I'm pretty sure it was wrong Reply Link to post Share on other sites More sharing options...
iber2011 Posted May 17, 2011 Report Share Posted May 17, 2011 In the aufbau principle one, I put all arrows up. As for the Kc question, I calculated the equilibrium concentrations using the x method and I think it turned out to be right. TO be honest, this wasn't a very difficult paper except for QUESTION 1 which was just a messed up question. paper 1 though was tricky. Really don't know what I'll get there! me too! i put all the arrows up....glad to know i wasn't the only one Reply Link to post Share on other sites More sharing options...
lolly89 Posted May 19, 2011 Report Share Posted May 19, 2011 For multiple choice, what did everyone get for the last question on significant numbers? I thought that was a very odd question since i was expecting something on accuracy/precision Hmmm I think my answer had something like 5 significant numbers? But I'm pretty sure it was wrong My answer had 5 significant figures too! coz it said the "best" possible answer. Although like you, I was starting to think it was wrong. I thought it was confusing because the values in the calculation didn't have the same number of significant figures! Or maybe I'm just stupid Reply Link to post Share on other sites More sharing options...
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