I’m beginning to wonder where it’s all going to end. With the event of the new equation writing format in 2007 I was not surprised (but nevertheless disappointed) to see that there was a new level of hand-holding for the candidates on this question. You will recall that ridiculous hints (like, “an oxidizing agent”) were added to some questions in a manner that they never had been in the past. Previously a candidate had to recognize the chemical in question was an oxidizing agent. Anyway, I was prepared to run with it in an attempt to give the CB the benefit of the doubt, but now that we have seen these overwhelmingly excessive hints three years in a row, it’s now time to call it as I see it.
I feel that this question is becoming close to invalid – yes, I’d go that far. It will start to fail to discriminate between good and bad candidates.
Of course, question #4 is the most obvious place that one sees this hand-holding, but there are lots of other examples too.
Consider this comparison from 2007 and 2003.
Question 1 in 2007 parts (c), (d) and (e) dealt with a reaction between HF and hydroxide ions. Here’s how it was set-up.
1. It gave the equation for the reaction between HF and and the base.
2. It TOLD the candidates to calculate the moles of HF remaining in solution, i.e. it TOLD the candidates that there was a limiting reactant.
3. It TOLD candidates to calculate the concentration of salt produced (a step needed for 4. below), which is a step the candidates used to be asked to work out was necessary for themsleves.
4. It asked candidates to find the pH of the solution, i.e apply find the pH of the buffer.
By giving SPECIFIC pointers (and points) by asking the questions separately, the questions were basically TELLING the kids that this was a buffer problem, and walking them carefully through the steps, but compare that to say, 2003 question 1 (c), where;
1. The equation for the reaction betweeen aniline and HCl is NOT given.
2. The reaction is not flagged as a limiting reactant problem so you had to work that out for yourself, and therefore you had to realize that it was a buffer.
3. A separate step was NOT included to flag the necessity for calculating the concentration of the salt.
4. The pH calculation was part of the whole question and the process was not broken down into individual steps.
As I say, there are plenty of other similar examples to the new level of hand-holding.