The encore by ethanoic acid, which followed up last year's performance in the chemistry paper by starring in question 2 this year, may have surprised some students.
Many students work on the basis that if was "there last year, it won't come up this year", noted Mr Ted Forde, TUI subject representative.
Overall, higher-level students at Ringsend Technical Institute, Dublin, found the paper long, he added.
Many questions contained a mixture of topics. For instance, question 7, the thermo-chemistry question, also included a section on industrial chemistry. Question 1, the short-answer question, was difficult and "hard to handle" Mr Forde said.
ASTI subject representative Mr Gerard O'Donoghue said the higher-level paper was "long and challenging and ranged over most of the topics on the syllabus. It was fair and balanced and students were happy with it."
The well prepared student should do well, said Mr O'Donoghue, who teaches in St Clement's, Limerick.
Students had to answer one of two practical questions and they should have had no difficulty as the topics were widely anticipated.
"Overall, I would welcome the paper. A new chemistry syllabus will be introduced in September 2000. This sort of paper and the new syllabus might encourage more students to take up chemistry," Mr O'Donoghue said.
At ordinary level, the questions were testing but fair. "And I was particularly pleased with the overall layout with the paper. It was very clear. "The language was clear, direct and precise and left students in no doubt as to what was expected."
As with the higher-level paper, this type of paper would make chemistry more accessible, he suggested. There was a good choice of topics and students, in general, should have been happy, Mr O'Donoghue said.
Sample Question from the ordinary-level chemistry paper
6(a) A sample of tap water is found to contain both calcium hydrogen-carbonate and calcium sulphate. These compounds cause hardness in water.
(i) What is meant by hardness in water? Distinguish between temporary and permanent hardness.
(ii) Which of the two compounds named above gives rise to temporary hardness? Write the chemical formula of this compound. Give a chemical equation showing how the compound can be removed from the water sample.
(iii) How is permanent hardness removed?
(iv) Give one advantage and one disadvantage of hard water. (b) Water treatment can be divided into a number of stages. State the purpose of each of the following: (i) flocculation; (ii) pH adjustment; (iii) chlorination; (iv) fluoridation; (v) filtration.