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Remember that the 1H NMR is giving you four types of information, and to look at each. 13C NMR gives three types. Recognise that NMR and IR also provide information on what is absent, as well as what is present.

Proofs 2 and 3 can be completed without using a calculator by simply continuing in fractions and doing the calculations manually.

I recommend avoiding the phrase "Ksp increases" or anything similar for any type of equilibrium constant because it has a high risk of leading a marker to think that you think equilibrium constants change value, which can only occur with changes in temperature. I appreciate that you mean Ksp...

Yes, the paper I wrote has brought multiple topics into single questions - equilibrium, organic, and polymers in q32, Ksp, titration, acids and bases in q28 - as other ways to make for challenging questions.

I provided four possible approaches in a thread posted in 2020.

Some of the questions come from examples that I have seen confuse students before - questions 1, 2, 5, and 9, for example. It helps that I have quite a lot of experience at secondary and tertiary levels, and also have qualifications in science and education. It also helps to have specialised...

Approach 1: \text{Since $\tan\theta = x$ and taking $x > 0$, $\theta$ is an angle in a right-angled triangle where the two non-hypotenuse sides are $x$ and 1.} \text{So, the length of the hypotenuse is $\sqrt{x^2+1}$ (applying Pythagoras' Theorem), meaning that $\sin\theta =...

Thank you for your comments and the solutions. You would have scored 19 / 20. :) Some specific comments / thoughts: It did not trick many students, however... 83% of respondents chose (B). Far too many did not go on to the second glance. Surprisingly, all four answers were selected at...

There was a Volhrad back titration asked.

I agree with Jazz that galvanic cells are unlikely, but anything in year 11 can be made contextually relevant to some aspect of the year 12 syllabus and hence examinable. For example, a galvanic cell with two inert electrodes and a solution containing Sn4+ cations and I- cations has a layer of...

I had a vision last night, of an HSC Chemistry student not scoring full marks on the MCQ by answering every question as A or C or D... I am predicting at least 1 MCQ will have B as its correct answer. I also forsee multiple questions relating to the element carbon and its compounds.

There won't be such a NESA document other than the syllabus, and it is written to give flexibility of what specific pracs to use. For example, you must do a prac showing Le Chatelier's Principle changes by adding materials, changing temperature, etc, but it doesn't have to be done using the...

\begin{align*} S &= A_{\text{base}} + A_{\text{sides}} \\ &= A_{\text{base}} + 4 \times A_{\text{side}} \qquad \text{since all 4 sides are identical} \\ &= x^2 + 4xh \end{align*} \begin{align*} \text{Since}\ V &= A_{\text{base}} \times h \\ 32 &= x^2 h \\ h &= \cfrac{32}{x^2} \\ \text{Putting...

It is \sin\theta, which you need to express in terms of x using the fact that x = \tan\theta.

Thanks for your solutions, and your comments. On q12(a), if I was marking the paper, I may well conclude that accepting both is the fairest outcome given the ambiguity that should have been addressed before the paper was finalised. This does not alter my view that the curve with a stationary...

For a problem like this, there is no need to do calculus to find the max / min... just observe that the area function is a quadratic and so it has a max or min at its vertex depending on the coefficient of x2. Also, it is clearer to write (10 - x)/4 rather than 10 - x/4 as the latter appears to...

Note: I have an errata note for the 2020 paper that says that q7 was meant to say position isomer. And Q18 was wrong in the answers to 2020 too.

that's the one I'm looking at... did you notice there is no correct answer to Q2?

I'm looking at 2021... I think you mean the 2020, where there is no correct answer for q7.

Are we looking at the same paper? I have Q4 as a functional group isomer of butanoic acid where the answer is the ester, D, as the alkanediol B is not an isomer at all. Q7 is about the copper(II) / ammonia complex. Q2 had no correct answer due to a typo in D. And, I had doubts about Q16