Hello Lauren, VSEPR theory cannot be used to give a precise answer for bond angles, hence the word estimate rather than, for example, determine. The bond angle depends upon both the domain geometry and the greater repulsion of the non-bonding...
HL Practice Paper 2 (1)Dear Geoffrey, For Q3(a) the command word is estimate. So my instinct is that they don't need to explain/justify/reason the method. So how would you allocate marks if only correct answer is given ie. <109.5.
HL Practice Paper 2 (1)You ask a good question Anjini. 1. Give your students plenty of practice with modelling kits so they can better envisage structures in three dimensions. 2. Students need to know that for enantiomers to...
HL Practice Paper 1 (Section A) (3)Any tips on how to explain question 37 to students?
HL Practice Paper 1 (Section A) (3)Yes thanks. New place, new perspectives, making me second guess my own understandings!
R2.2 (AHL) Activation energyHi Darren, If I can just expand upon Paul's answer to your question. I think you are correct that this is really an HL question. It is worth looking at the subject report which states: "Question 3 challenged students to derive the...
The subject report and errors in the exam papersHi Darren That's a good point! The guide doesn't explicitly state that the students are expected to do this. It does, however, say in R2.3 that (SL) students should 'Deduce the equilibrium constant expression from an equation for a homogeneous...
The subject report and errors in the exam papersHi ManiWhen we plot a graph of lnk against 1/T to find the activation energy, we derive Ea from the gradient, of course. So, on the y-axis we can plot the natural log of anything that is proportional to...
R2.2 (AHL) Activation energyHi Geoff, I was looking at the May 2025 TZ3 SL Q3a, it asks students to calculate the value of K. Is that not HL only? I checked the guide and I can only see K calculations in HL. Am I wrong? Darren
The subject report and errors in the exam papers
Anjini
Thank you so much Geoffrey! This was really helpful and I appreciate the tips in helping my students understand this more clearly.
HL Practice Paper 1 (Section A) (3)