The Leaving Cert chemistry papers were described by one teacher as a "good advertisement" for a subject which has been struggling to attract students.

Pat Hanratty of Tallaght Community School said yesterday's papers were more student-friendly, continuing a trend evident since the new syllabus was introduced four years ago.

Students and teachers reported few major problems with the chemistry papers.

Mr Hanratty said the higher-level paper was "much more manageable" than in previous years. However some of its questions were demanding and searching.

Among other questions, students were asked about Roy Plunkett, the Du Pont chemist who discovered Teflon, and Henri Becquerel who discovered radioactivity.

The only major complaint yesterday was about the lack of time available. Higher-level students are required to answer eight questions in three hours.

Teachers reported that virtually all students remained in the exam hall until 5pm to complete the exam.

The ordinary-level paper was described as "fine and straightforward" by students.

The number of students taking chemistry has declined sharply in recent years, reaching an all-time low of 6,935 last year. This year, the numbers are up again, to 7,623. The reversal has been attributed to the new chemistry syllabus, examined for the fourth year yesterday.

In recent years, Government, employers and teachers have been working to arrest the fall-off in interest in science subjects, but there is more work to be done. Just over 4,000 students took higher-level chemistry yesterday, only 7 per cent of those taking the Leaving Cert exam.

There is evidence to suggest that some students are reluctant to take science subjects because of their relatively high failure rates. Last year, 17 per cent of students failed higher-level chemistry, while 9 per cent failed the ordinary-level paper.

Two years ago, there was controversy when the higher-level paper featured a question not based on the syllabus.