How to Get a H1 in Leaving Cert Chemistry

If you are sitting Leaving Cert Chemistry in 2027 or later, you are on the new specification, and a H1 on it means 450 marks out of 500. The State Examinations Commission splits those 500 across two components. A written paper carries 300 and the Chemistry in Practice Investigation carries 200. For the first sitting, the investigation has to be finished by Friday 23 April 2027. Two fifths of your grade is therefore settled in April, before the written exam.

September 2025 is the line that matters

The cover of the Leaving Certificate Chemistry specification reads "For introduction to schools in September 2025". The National Council for Curriculum and Assessment, which writes the specifications, puts the changeover plainly on its chemistry development page:

A new specification for Leaving Certificate Chemistry has been developed, to be introduced for fifth year students in September 2025, replacing the current Leaving Certificate Chemistry syllabus which will be examined for the last time in June 2026.

Fifth years who started in September 2025 reach sixth year in 2026/27, and the SEC has published their assessment materials already, including sample papers coded 2027 and a live investigation brief headed 2027. If you are sitting chemistry in 2027 or any year after it, the new specification is the only one that applies to you.

Chemistry sits in the first tranche of Senior Cycle Redevelopment, the programme rewriting each Leaving Cert subject. The SEC's Senior Cycle Redevelopment page groups it under the heading "New and revised subjects for introduction in schools in September 2025", with Biology, Physics, Business, Climate Action and Sustainable Development, Drama, Film and Theatre Studies, Ancient Greek, Arabic and Latin. Biology is in the same position, and our post on how to get a H1 in Leaving Cert Biology covers that subject's version of the same changes.

Anyone who sat chemistry up to June 2026 took a different exam. Page 1 of the 2019 Higher Level paper sets out what that was:

Answer eight questions in all.

These must include at least two questions from Section A.

All questions carry equal marks (50).

That paper ran 400 marks over three hours, from 2:00 to 5:00. Eleven questions were printed and you answered eight of them. Section A held the three questions on the mandatory experiments. The Section A requirement quoted above was dropped from 2021 onwards under the assessment adjustments, so the 2023 to 2025 papers said simply "Answer any eight questions", and the 2021 and 2022 papers ran shorter still at 300 marks from any six. None of that describes the paper ahead of you, so revision advice built on picking questions from eleven is advice for a cohort that has already left.

The course content is organised differently too. The old syllabus was a core plus options, and it named 28 mandatory experiments that Higher Level students had to carry out and keep a record of. The word "mandatory" does not appear in the new specification, and there is no prescribed experiment list in it. Content is now set out in five strands, one unifying strand called The Nature of Science and four contextual strands, Nature of Matter, Behaviour of Matter, Interactions of Matter, and Matter in Our World. Both courses are designed for 180 hours of class contact time.

Seven questions, six answered, no sections

The SEC has published two Higher Level sample papers and two at Ordinary Level. Higher Level Sample 1 runs 2 hours 30 minutes for 300 marks, and its instructions on page 2 open with this:

There are seven questions on this paper. Each question carries 50 marks.

Answer Question 1 and any five other questions.

Sections A and B are gone. Seven questions are printed, all worth 50, and you answer six of them in 150 minutes. Question 1 is compulsory, so choice begins at question 2 and a topic you have quietly dropped can still reach you.

Question 1 in that sample runs from page 3 to page 7 and has five parts. Part (a) reads line emission spectra off a diagram. Part (b) applies Hess's law to calculate an enthalpy change. Part (c) defines first ionisation energy and asks about exceptions to the trend across period 2. Part (d) asks for a diagram of dipoles and intermolecular forces between propanone and water. Part (e) describes how to make up a solution of iron(II) from tablets. That is five different areas of the course inside the one question you cannot skip.

Three more lines on that instructions page bear on how you practise calculations:

The superintendent will give you a copy of the Formulae and Tables booklet. You must return it at the end of the examination. You are not allowed to bring your own copy into the examination.

Data from the Formulae and Tables booklet, including atomic numbers and relative atomic masses, should be used wherever necessary.

You may lose marks if your answers are not given in their simplest form, where relevant.

The old papers printed the data you needed on the cover. The 2019 cover listed relative atomic masses, the Avogadro constant, both molar volumes and the universal gas constant. The new paper prints none of that and points you to the booklet instead, sometimes by page. Part (c) of that first question tells you to examine the first ionisation energies "on page 80 of the Formulae and Tables booklet". Finding a value quickly in a booklet you have used all year is now part of the exam.

One more change is physical. The paper is an answer booklet that gets scanned, and you write into the boxes provided, so work in the margins may never reach an examiner.

The investigation is 200 marks and it is due in April

Page 2 of the SEC's sample brief puts the Chemistry in Practice Investigation at 200 marks and 40 per cent of the subject, leaving 300 marks and 60 per cent to the written paper. The NCCA specification carries the same two weightings in its table of assessment components.

The live brief for the 2027 examination is already published, and its topic is the control of reaction rates. It asks students to investigate how factors including concentration, surface area, temperature, pressure and the presence of a catalyst change how fast a reaction goes, set against uses in health, sustainability and technology. If you want to see how that material has been examined before, the rates of reaction topic page collects the past questions on it, and the volumetric analysis page covers the measurement techniques a rates investigation tends to lean on.

Page 2 of the live brief gives the deadline in one sentence:

The coursework must be carried out and submitted to the class teacher by Friday, 23 April 2027 and will then be submitted to the SEC (Section 3).

That date is late compared with the other redeveloped sciences. The same schedule of examination and completion dates for 2026/2027 puts the Physics in Practice Investigation on Friday 11 December 2026 and the Biology in Practice Investigation on Friday 26 February 2027. Chemistry students carry their coursework into the final term, alongside revision for every other subject.

The work itself is prescribed in some detail. The specification envisages the investigation taking up to 20 hours to complete, across six stages that run from a first response to the brief through background research, design, the experiment itself, data analysis and the write-up. You run the experiment under supervision, with the brief stating that gathering your primary data "must be fully completed under the direct supervision of your Chemistry teacher". You then write a report under seven headings, from Title and Introduction through to References. The report is capped at 1,500 words and 20 images, and the brief is direct about what length costs you:

Note that your report will gain marks for communicating clearly and with skilful brevity, but that fewer marks will be awarded if your report loses coherence through unwarranted length.

The 200 marks arrive in four equal blocks of 50, set out on page 8. Three of them follow the report's own structure, covering your research and referencing, your design and conduct of the experiment, and your data and conclusions. The fourth is Scientific Literacy, judged across the whole document rather than in any one section.

The brief also requires you to reference and acknowledge your research sources, "including any use of AI". It states that including material you did not create without referencing it counts as plagiarism, and that the SEC will investigate it. Using a tool to understand a concept is study. Submitting its words as your report breaks the coursework rules.

What the 2015 to 2025 papers still teach

The specification changed the assessment, and much of the chemistry carried over with it. Atomic structure, bonding, thermochemistry, rates, equilibrium, volumetric analysis and organic chemistry all appear in both courses, and all of them turn up in the new sample paper. Our corpus holds the 11 Higher Level papers from 2015 to 2025, which come to 121 questions.

Organic chemistry is the largest single area. It appears in 43 of those 121 questions, and in every one of the 11 papers, three to five times each. The organic chemistry, hydrocarbons and fuels topic page groups those questions with the marking scheme beside each one. Our post on how many past papers to do uses that same count to show how long one topic in one subject takes to work through properly.

Calculation runs through the rest. The instruction "calculate" appears in 75 of the 121 questions, in all 11 papers. The new sample paper keeps that weight, asking in question 1 alone for an enthalpy change by Hess's law.

Practical work reaches well past the old Section A. 58 of the 121 questions mention an experiment, a technique or a named piece of apparatus, and 28 of those sit in Section B, outside the experimental section. That content has carried over. Question 1(e) of the new sample paper asks how a student would make up an exact volume of iron(II) solution from tablets. Question 1 of the 2025 Higher Level paper sets an experiment on the same iron tablets, through a volumetric flask and a titration against potassium manganate(VII). The laboratory skills and techniques page collects that kind of question across the years.

Marks come off one at a time

Chemistry marking schemes take marks off for specific, small things, and at 90 per cent there is not much room for them. Page 3 of the 2025 Higher Level marking scheme lists the deductions:

Each time an arithmetical error occurs in a calculation, one mark is deducted.

For drawing the molecular structure of an organic compound, one mark is deducted if the H atoms are omitted in a systematic way and one mark is deducted if bonds to H atoms are omitted in a systematic way.

For omission of appropriate units (or for incorrect units) in final answers, one mark is deducted, unless otherwise indicated.

The same page sets out how far a name has to go. When you are asked to identify a chemical substance, either the name or the formula is accepted, "unless otherwise indicated". For organic compounds the IUPAC name is required. Question 2 of the new sample paper asks for the IUPAC name of two alcohols drawn as 3D models, so that rule has somewhere to bite.

On the old 400-mark paper a H1 started at 360, which left 40 marks across the eight questions you answered. Each of these deductions is worth one mark, so they accumulate at a rate you can count. Writing the unit on a final answer and putting every hydrogen into a structure cost nothing in the exam hall once they are habits.

One caution comes from the SEC itself. It prints in every scheme that assumptions about future marking schemes should be avoided on the basis of past ones, and no scheme has been published for the new paper. Our post on how Leaving Cert marking schemes work goes through the annotation symbols in the table on page 4 and what each one records.

Is chemistry hard for the Leaving Cert?

In 2025, 17.8 per cent of the 8,577 Higher Level chemistry candidates got a H1, second among subjects with more than 5,000 candidates at that level. Our post on H1 rates by subject has the full table. A H1 rate depends on who sits the subject, so it compares cohorts as much as it compares subjects. The same post shows the chemistry rate moving from 23.2 to 22.4 to 17.8 per cent across 2023, 2024 and 2025, so the figure is not fixed either.

Chemistry's grade bands come from the common scale, covered in our post on Leaving Cert grades, so a H1 here carries the same 100 CAO points as one in any other subject.

What is particular to chemistry is the shape of the work. Two hundred of your marks come from an investigation with published criteria, a word limit and a deadline in April. Three hundred come from one 150-minute paper that opens with a compulsory question sampling five areas of the course. Neither is small enough for the other to cover.

FAQ

What percentage do you need for a H1 in Leaving Cert Chemistry? 90 per cent, which in chemistry now works out at 450 marks from the combined total of 500.

How long is the new Leaving Cert Chemistry exam? Every published sample paper, Higher and Ordinary, gives 2 hours 30 minutes and 300 marks. The paper it replaces was three hours and 400 marks.

How many questions do you answer on the new chemistry paper? Six of the seven printed, each worth 50 marks. Question 1 has to be attempted, and the choice is any five from questions 2 to 7. The paper has no sections.

What is the Chemistry in Practice Investigation worth? 200 marks, or 40 per cent of the subject. It is submitted as a PDF report, with a ceiling of 1,500 words and 20 images.

When is the Chemistry in Practice Investigation due? Friday 23 April 2027 for the first sitting, the date given in the live brief and in the SEC's schedule of completion dates for 2026/2027.

What is the 2027 chemistry investigation about? The control of reaction rates, including the effects of concentration, surface area, temperature, pressure and catalysts.

Is chemistry hard for the Leaving Cert? 17.8 per cent of Higher Level candidates got a H1 in 2025, which was high relative to most large subjects. That rate says as much about who sits chemistry as about the subject.

Are the old chemistry papers still useful? Yes, for the chemistry itself and for the phrasing of questions. What they cannot show you is the layout, since the papers sat up to 2026 were split into Sections A and B and ran to 400 marks over three hours in most years, with the 2021 and 2022 papers shortened to 300.

The ExamAI tutor works through real Leaving Cert chemistry questions with you, one part at a time, with the official marking scheme for that question in front of it. It asks how you would start before it shows you anything, then tells you where your working earned marks and where a unit or a step went missing. That is what making learning personal means here.