HSC Chemistry data sheet and formulae sheet explained (NESA)

The HSC Chemistry exam set by NESA gives you a formulae sheet, a data sheet and a Periodic Table at the back of the booklet. The formulae sheet holds a short set of core equations and constants. The data sheet holds solubility constants, infrared, ¹³C NMR and UV absorption data, and standard electrode potentials. It does not hold any equilibrium expressions or a table of acid constants, so you still have to know those.

This guide describes the sheets printed in the 2025 NESA HSC Chemistry examination (PDF pages 41 to 44). The 2023 and 2024 papers also carry them but were not compared line by line, so confirm the sheet in any other paper you practise on. This page annotates the sheets and links to the original instead of reprinting it: open NESA's 2025 HSC Chemistry exam pack and read the last pages of the paper alongside this guide. It applies to the HSC Chemistry course (Year 12 exam). For past papers see HSC Chemistry past papers (NESA), and for the exam's topic weightings see HSC Chemistry most tested topics.

What is on the HSC Chemistry formulae sheet?

The first page of the sheets holds a short list of equations, then a short list of constants.

• Equations. They cover moles from mass and molar mass, concentration from moles and volume, the ideal gas equation, heat from temperature change, Gibbs free energy, pH, $\mathrm{p}K_a$ and absorbance. Use the first two for any stoichiometry, titration or dilution question, the gas equation when the gas is not at one of the printed molar volume conditions, and the heat equation for calorimetry. Use the Gibbs equation to decide spontaneity, the pH and $\mathrm{p}K_a$ lines for any acid question, and the absorbance line for UV-visible questions linking absorbance to concentration.
• Constants. They include Avogadro's constant, two molar gas volumes at different temperatures, the gas constant, the ionisation constant for water and the specific heat capacity of water.

Two details are easy to misread. The specific heat capacity is per kilogram, so a 250 g sample is 0.250 kg in the heat equation. And there are two molar gas volumes, so pick the one that matches the temperature in the question before you reach for the ideal gas equation. The Gibbs equation needs the temperature in kelvin.

What is on the HSC Chemistry data sheet?

The data sheet has five blocks, and each one answers a different kind of question. In the 2025 paper they sit on PDF pages 41 to 43, and the Periodic Table follows on page 44.

Solubility constants ($K_{sp}$) at 25 °C. Values for a range of salts, covering barium, calcium, copper(II), iron(II), iron(III), lead(II), magnesium and silver compounds (carbonates, hydroxides, phosphates, sulfates and some halides). You get the number. You do not get the expression, so write it from the dissociation equation.

Infrared absorption data. Wavenumber ranges in cm^-1 for the common bond types: N-H, O-H, C-H, C≡N, C=O, C=C, C-O and C-C. Read the O-H entries closely, because the alcohol and acid ranges are described differently (broad against very broad), which is how you tell them apart in a spectrum.

¹³C NMR chemical shift data. Ranges in ppm for carbon environments, from saturated carbons at the low end to aldehyde and ketone carbonyls at the top. The environments are drawn as structures on the page, so read the drawn structure and not just the number.

UV absorption. A short table of $\lambda_{\max}$ values for a handful of chromophores. The sheet itself says it is not a definitive list and is approximate.

Standard potentials. A list of half-reactions with values in volts, running from strong reducing agents to strong oxidising agents. The sheet's note says the principal source is Aylward and Findlay, SI Chemical Data (5th edition), and that some data may have been modified for examination purposes. So use the number on your sheet, not the one in a textbook.

The Periodic Table is on the page after. Its footnote says atomic weights are abridged to four significant figures, which matters when your molar mass feeds a significant-figure decision.

What is not on the HSC Chemistry sheet?

The sheet is a source of numbers and a few core equations, not a summary of the course. In the 2025 paper it does not give you:

• The expression for $K_c$, $K_{sp}$ or $K_a$ (you write them from the balanced equation).
• A table of $K_a$ or $K_b$ values for named acids and bases. The only acid constant link is the $\mathrm{p}K_a$ equation.
• Rate laws.
• Boiling points, enthalpies of combustion or bond energies.
• Proton NMR data. Only ¹³C NMR is printed.

If a question needs a value that is not on the sheet, look for it in the question and its stimulus.

How do exam questions use the data sheet?

NESA's marking feedback for 2024 and 2025 points at the sheets in a few Section II questions, and its advice on calculations applies to every value you take from them. Paraphrased:

• Spectroscopy questions want both sources. On the 2025 question that asked for predicted spectra across four techniques, better responses used an annotated structural formula, drew on spectroscopic data from both the stimulus and the data sheet, and gave only the data relevant to the compound. In 2024, better responses to a spectroscopy question used the sheet's ¹³C NMR data.
• Show the substitution. For 2025 equilibrium and titration questions, NESA's feedback asks students to write the expression, substitute the values, and show each step, including $c = \dfrac{n}{V}$ and the $K_a$ expression in the pH curve question.
• Significant figures and units. NESA's general feedback for both years asks students to show working with correct units and significant figures, and a 2025 calculation question called out significant figures specifically. A 2024 $K_{sp}$ question wanted the $K_{sp}$ expression written first and the answer to 3 significant figures.
• Find the value, then use it. NESA's general feedback asks students to engage with the stimulus. On a 2025 question about the acidity of the hydrazinium ion, better responses took $K_w$ from the data sheet and used it to find $K_a$. On a 2025 precipitation question, better responses used the $K_{sp}$ values to decide which precipitate forms first, and NESA listed reading scientific notation (that $10^{-7}$ is larger than $10^{-12}$) as an area to improve.

These are Section II findings. NESA publishes no feedback on the multiple-choice section.

To see how these play out on marked questions, work through solution equilibria, calculating the equilibrium constant, quantitative analysis and analysis of organic substances. Our wider data on where students drop marks is in HSC Chemistry hardest topics.

Common mistakes with the sheets

How to practise with the sheet

Download the 2025 sheets from NESA's PDF once and keep them beside you for every practice paper, so you stop hunting for where a value lives. Then use the marked questions on the HSC Chemistry page, which hold the questions from the 2023, 2024 and 2025 NESA papers. For the board's rules on calculators and exam conditions, see HSC exam preparation, and for the paper library see HSC past papers.