Hi Darren,It. is a very poorly worded question. They should have asked for the answer in kJ, not kJ mol-1. See my reply...
The subject report and errors in the exam papersHi Geoff/Paul, I was looking at this May 2025 TZ1 SL Q19, it is about the enthalpy change of the reaction, the answer given is C, but I don't get why they divide the limiting reagent by 3 to get 12.5 rather than use the limiting reagent as the number...
The subject report and errors in the exam papersHi Mani,You can find out about the use of extrapolation in chemistry on the page on Graphing techniques and...
R1.1 Measuring energy changesHi, I have 2 questions about extrapolation for a displacement reaction calorimetry data. Would it be wrong to extrapolate all the way to the y axis and then use the difference between y axis intercept and initial temperature? Is...
R1.1 Measuring energy changesHi Tshering,Students need to work out the original amount of hydrochloric acid added and the amount of hydrochloric acid remaining (i.e. the excess acid) from the acid-base titration with sodium hydroxide after the reaction with the dolomite....
SL Practice Paper 2 (1)Question 1 d assumes that the students understand that titrations are also used to determine unreacted amounts of acid (in this context). Is this required as a part of the new syllabus. I could not find anything in the syllabus guide, tools, or inquiry,...
SL Practice Paper 2 (1)I, like students got tricked by the wordings, yes they should have used kJ.
R1 What drives chemical reactionsThank you for this detailed response.
R1 What drives chemical reactionsHi Mani, This question was Question 19 on the SL M26 TZ1 Paper 1(A) and question 23 on the corresponding M26 HL Paper 1(A). This was a hard question for a multiple choice exam. The SL Subject report stated"A very challenging question for...
R1 What drives chemical reactions
Mani
Hi, If Ea is to be found from the Arrhenius plot for clock reactions, when rate=1/t, is it justified to assume k = rate. This is so that lnk values can be obtained.
R2.2 (AHL) Activation energy