Higher chemistry was more difficult than in recent years, but still fair, according to Joe Farrell.
The principal chemistry teacher at Gourock's St Columba's High always expects three or four multiple-choice questions in Section A that would not be found in past papers, but there seemed to be more "refreshingly new" questions this year.
The first part of Section B was "fairly routine", and Mr Farrell was pleased with the continuation of a trend whereby one question demands literary skills: a short paragraph explaining why hydrogen is a gas at room temperature. "We welcome that because it goes against what people say - that chemistry and physics are just numbers," he said.
The paper was much harder between questions 11 and 17, however. Question 11, which demanded an explanation of the mistake in reasoning shown by a student's answer, may have thrown some candidates, although this should not have been too unfamiliar a task, as the school is attempting to embed Assessment is for Learning across the curriculum through techniques such as peer assessment.
There were several "very challenging" questions involving problem-solving, including two requiring pupils to predict the two-dimensional alignment of molecules after a reaction - "a mature skill for Higher pupils". Mr Farrell was confident, however, that well-prepared pupils would have picked up enough marks earlier to gain a C, even a B.
He believes Intermediate 1 and 2 suffered from questions that required "far too much reading", with information hidden in passages, although the exams were fair overall.
Advanced Higher was "reasonably difficult but no worse than expected at this level". There was an unusual question worth three marks on partition coefficients, balanced by a straightforward three marks on reaction rates.