What do I mean

The hypothetical questions above dont give a lot. On the face of each one, its not obvious what the parameters of the question are. Where do you start? How much detail do you need to go into? But if you know what clues to look out for, the questions actually tell the student exactly what they need to do.
Lets take the first question: Describe and explain the differences between the reactions of sodium and water and aluminium and water. On the face of it, this seems like a very broad question. Where on earth are you supposed to start? The magic words in this question are describe and explain. These words are the kinds of signals your teen needs to be on the lookout for.