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Chemistry (New Syllabus)
IB DP Category 2
Stockholm, Sweden, 12 - 14 May 2023
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Chemistry (New Syllabus)
IB DP Category 2
Online (IB Approved), 25 - 27 August 2023
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Subscriber comments
(Last 3 months)
- Thank you for the explanation. Interesting idea about the non-polar connection with not being a ligand. Thanks again for taking the time to explain this.
- Hi Renuka, The carbon to oxygen bonding in the ethanoate ion CH3COO– is a good example of resonance. The bond order is 1.5 as the C=O and C–O bonds can be drawn as two resonance hybrids so the two bond lengths and strengths are equal. Alternatively...
- The question 5 in bonding test 2 SL is comparing the bond length between C and O in different molecules. According to the answer, the bond lengths between C and O in acetate ion are the same. Could you please explain it to me. Is the electrons...
- Hello Renuka, Yes, it is wrong. Ba2+(aq) and NO3–(aq) do not react as they are spectator ions so do not change. The reaction is between Ag+(aq) and Cl–(aq) ions which combine to precipitate silver chloride (which can be written either as...
- Dear Prof, The second question " Particulate nature of matter and chemical change" is asking ionic equation. You wrote Cl- + Ag+ --- AgCl as the ionic equation for the reaction between barium chloride and silver nitrate.Is it wrong...
- Thank you Prof. Now I do understand her results.
- Hi Amy, Unlike ligands such as H2O and NH3 etc., SiCl4 does not contain a non-bonding pair of electrons around its central atom so does not act as a ligand. In fact, unlike CCl4, it can act as a Lewis acid rather than a Lewis base as it is...
- Hi Geoffrey,On number 15, can you please explain why SiCl4 dose not act as a ligand. Thanks!
- Thank you, Dr. Geoff.That was very elaborate.
- Hi Jack,This is Qu. 29 in the November 2022 SL exam (and Qu. 39 on the HL paper). I don't think it is well worded as the question 'talks' about idea and prediction whereas all the answers 'talk' about theory and hypothesis which are not necessarily...
- Hi Dr. Geoff,Could you help with this?A well tested scientific idea which has been used to make predictions cannot explain a particular event. Which statement describes the scientific approach to this dilemma?A. Hypothesis should be discardedB....
- Thank you, Geoff! :) I didn't think you would reply so fast. I appreciate it.
- Hi Charmaine, Happy to help. It is Question 5 on Further aspects of covalent bonding questions.
- Hi Geoff, I was hoping you could help me find a question, please. I've already searched it up on my own but I still can't find it and I'm quite sure I got the question from this site. Here's the question: "Ultraviolet light can break the oxygen-to-oxygen...
- Hi Austin, No, I don't think so. All four of each carbon atom's valence electrons are used in the bonding in graphite. Three of them form sigma bonds to three other carbon atoms and the fourth is delocalised forming weak attractions (i.e. a...
- For question 6, could option (b) not also be possible?
- Hi Amy, One of the problems with the IA is that what examiners are told to look for seems to depend more upon what is written in the subject reports than what is written in the subject guide and has changed somewhat since this syllabus started...
- Our IB Chemistry teachers are trying to get better at helping students with their evaluations. Do you have any additional resources on this site that explain what is on this page better (or suggestions on IB specific resources we could use)....
- Hi Renee, Although the IB has issued several releases about the new subject guide (e.g. see my blog) the new 2023 guide is not due for publication until early next year (probably February). Once it is in the public domain (i.e. on My IB) this...
- Hi Mr Neuss- has the new syllabus's subject guide been published anywhere yet? Or are we still waiting until after new year?
- Leo, The easiest thing to do is sign your students up to student access then you can set the exam as an assignment and their answers will be marked automatically and then transferred directly to your mark book The students will also be able...
- Hi. I am a chemistry teacher in Japan. Can anyone tell me how to download those papers as prinatble version?
- Hi Dea,A plot of ln t against 1/T gives a straight line with the gradient = Ea/R (see teacher's notes above) so the activation energy = gradient multiplied by R (not divided by R). If the gradient = 5696.1, then...
- the gradient from Cleaps's data is 5696.1. Divided by R value becomes, 685.4 J. How come it is said that the result is 47kJ?
- Hi Margarethe,I have not provided answer sheets for the questions on the practical worksheets as many of them involve students using data that they themselves have obtained (e.g. questions 2 and 3 above) so the answers will be different for...
- Hi, are there answer sheets available for these mandatory practicals? can not seem to find them
- Thank you! :) Very useful.
- Hello Philip, If you look at the "syllabus outline" (p18-21) in the current guide you will see that these are recommended teaching hours. They add up to 110 hours for SL and 180 hours for HL with the remaining 40/60 hours for the Practical...
- Hi Geoffrey, where is gives suggested number of hours for each topic (e.g. Topics 8 ( 6.5 h) & 18 ( 10 h) : Acids and bases) in the Teachers view, are these hours spent teaching or hours spent learning ? (I am guessing that former, since...
- Hello Renuka, Have you considered the fact that the Winkler method involves the formation of iodine from iodide ions and the more chlorine that is present the greater the formation of iodine? This will make it appear that the amount of dissolved...
- Dear Prof Jeff,I am Renuka from Norway and attended to several workshops of yours in Berlyn. I am working in Blinder VGS in Norway. One of my students wanted to test "the effect of chlorine content on dissolve oxygen level in water". So...
- Hello again Xiaodan,It is not very clearly expressed in the report which I suspect was written by a non-native speaker of English as there are several slightly strangely worded sentences and often a reference to how Spanish rather than English...
- Hello Dr. Neuss,Thank you so much! It is reassuring to know that I am not the only one who is confused about the statement. On the second note, I would to have some help with checking my understanding on this section from the subject report,...
