ketone Posted May 16, 2015 Report Share Posted May 16, 2015 I did option B and E... they were alright I think. Better than other papers : ) what did you get for question of the comparing structures of ketone and aldosterone? Ketone and aldosterone? Did you mean cholesterol and aldosterone? sorry...yes it should be cholesterol and aldosterone..i mess up with my name Reply Link to post Share on other sites More sharing options...
Hassan76 Posted May 16, 2015 Report Share Posted May 16, 2015 I'm SL but I wrote loss of heat to surroundings, which will change the real value /affect the temperature, and since it's a random error because also some air can flow into the container.... So it can be reduced by repitions and it was asked in p1 also Reply Link to post Share on other sites More sharing options...
slimshady Posted May 16, 2015 Report Share Posted May 16, 2015 (TZ2) I'm super frustrated with the amount of silly errors I made in paper 2 (not reading the question properly, unit conversions etc.) I hope it won't have cost me a 7. I cannot remember which question this was, probably 9, but we had to work out the bond angle of SF4. I got the shape right but I never learnt or came across bond angles for see saw shapes so I guessed 107. What did you guys get for that?I said the same thing. 107 for one and <120 and<180 for the other one.both had a lone pair. What did you writr for the question were they asked about the covalent bond between hydrogen and carbon? So the bond angles for the seesaw should be more than 180 so 186 because of the pair of lone electrons that has extra repulsion, less then 120, so 116 and exactly 90 so 186,116 and 90. I was blessed with this question as I wrote all of the shapes and bond angles on paper night before the exam and memorised I think that Pearson's HL book is great for learning bonding cuz in Study Guide they do not pay attention to shapes and bond angles. Reply Link to post Share on other sites More sharing options...
slimshady Posted May 16, 2015 Report Share Posted May 16, 2015 about the source of error in the 1st question, it couldn't be lost of heat, I guess that it was that the student used a glass beaker to measure the solutions (as it was written in the text) so I wrote that the improvement might be using the graduated cylinder instead of glass beaker, I am suprised that you have written lose of heat like all of my friends wrote glass beaker Reply Link to post Share on other sites More sharing options...
slimshady Posted May 16, 2015 Report Share Posted May 16, 2015 what did you got for the number of mol in the 1st question in paper 2 tz2? Reply Link to post Share on other sites More sharing options...
dorianb Posted May 16, 2015 Report Share Posted May 16, 2015 (edited) 0.025 I believe.. Edited May 16, 2015 by dorianb Reply Link to post Share on other sites More sharing options...
slimshady Posted May 16, 2015 Report Share Posted May 16, 2015 0.025 I believe... the same here Reply Link to post Share on other sites More sharing options...
dorianb Posted May 16, 2015 Report Share Posted May 16, 2015 0.025 I believe... the same here What Did you get as the concentration? Reply Link to post Share on other sites More sharing options...
slimshady Posted May 16, 2015 Report Share Posted May 16, 2015 What did you all write for q1 in option B? It was the question about chromatography and I think it was someting about how the amino acid is prepared for chromatography? I wrote that the protein by the use of HCl is separated into amino acids... but i know it is wrong ... Reply Link to post Share on other sites More sharing options...
koko122 Posted May 16, 2015 Report Share Posted May 16, 2015 about the source of error in the 1st question, it couldn't be lost of heat, I guess that it was that the student used a glass beaker to measure the solutions (as it was written in the text) so I wrote that the improvement might be using the graduated cylinder instead of glass beaker, I am suprised that you have written lose of heat like all of my friends wrote glass beaker Why couldn't it be a thermal energy loss? Reply Link to post Share on other sites More sharing options...
slimshady Posted May 16, 2015 Report Share Posted May 16, 2015 0.025 I believe...the same here What Did you get as the concentration? sorry I don't remember :/ I only remember that i got near 19% percentage error and that the enthalpy was near 47. I gues that I have that wrong. Reply Link to post Share on other sites More sharing options...
dorianb Posted May 16, 2015 Report Share Posted May 16, 2015 Well I got 22%, but used the wrong delta T, so :/ bot for the conc I got something like 0.0833.. Reply Link to post Share on other sites More sharing options...
slimshady Posted May 16, 2015 Report Share Posted May 16, 2015 Well I got 22%, but used the wrong delta T, so :/ bot for the conc I got something like 0.0833.. Well delta T i got 5.6 and my friends got like 5.2 or 5.0 or 5.4 so I hope that there will be a wide range for the answer.... Reply Link to post Share on other sites More sharing options...
koko122 Posted May 16, 2015 Report Share Posted May 16, 2015 What was the source of error in question 1? Reply Link to post Share on other sites More sharing options...
dorianb Posted May 16, 2015 Report Share Posted May 16, 2015 What was the source of error in question 1?Wrote heat loss, and proper insulation by use of bomb calorimeter as improvement Reply Link to post Share on other sites More sharing options...
koko122 Posted May 16, 2015 Report Share Posted May 16, 2015 (edited) the student carried out the experiment in a glass beaker so loss of thermal energy right? Transfer of thermal energy between the surroundings and the system Edited May 16, 2015 by koko122 Reply Link to post Share on other sites More sharing options...
ketone Posted May 16, 2015 Report Share Posted May 16, 2015 the student carried out the experiment in a glass beaker so loss of thermal energy right? Transfer of thermal energy between the surroundings and the system What was the source of error in question 1?Wrote heat loss, and proper insulation by use of bomb calorimeter as improvement I agree, definitely heat loss to surrounding as source of error I think. I would appreciate if you could help with my topic: http://www.ibsurvival.com/topic/34421-chemistry-ia-moderation/ Reply Link to post Share on other sites More sharing options...
Hassan76 Posted May 16, 2015 Report Share Posted May 16, 2015 I did TZ2 and tbh Paper 1 i was unsure of some but it wasn't hard. And Paper 2 was a breeze it was so great (except for explaining why engineers would use Aluminium over Iron, i just said its cause Aluminium is the most abundant mineral in the Earth's crust cause it is ) For P1 TZ2, You remember what you guys wrote for that electroylsis question? The one with hydrogen/oxygen something produced at both ends? I said both produce the same amount of oxygen.Anyone with answers for the buffer question in section A p2 tz2? Yeah! It was 0.01 mol/dm^3 for the concentration. I used the Henderson-Hasselbalch equationI said al has less melting and boiling points so would be obtained more easily from fractional distillation Reply Link to post Share on other sites More sharing options...
Hassan76 Posted May 16, 2015 Report Share Posted May 16, 2015 about the source of error in the 1st question, it couldn't be lost of heat, I guess that it was that the student used a glass beaker to measure the solutions (as it was written in the text) so I wrote that the improvement might be using the graduated cylinder instead of glass beaker, I am suprised that you have written lose of heat like all of my friends wrote glass beaker Why couldn't it be a thermal energy loss?For this reason, the question asked for the "major" error which in my p of view is loss of heat 1 Reply Link to post Share on other sites More sharing options...
kw0573 Posted May 16, 2015 Report Share Posted May 16, 2015 (TZ1) For paper 1, what was the answer to what would change the Kc value. I put C (increase in concentration) but I'm not sure.There was another question where there was two arrows. It went something like hydrocarbon -- X -- CH3CH2NH2 and said find x? Does anyone remember it. For paper 2, I remember doing 6 and 8 for section B. I wasn't sure about the economic need for catalyst in the contact process on question 6? Left a whole pH question blank even though I knew the ph = pKa - [weak acid]/[base]uh I put no change for that one. I thought Kc is only depended upon temperature. Since it was constant temp i think Kc remains the same. Reply Link to post Share on other sites More sharing options...
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