A-Level Chemistry Notes & Physical Chemistry Practice

A-LEVEL CHEMISTRY • NOTES + CALCULATION PRACTICE

A useful route through physical chemistry

Find the topic notes you need, then practise the mathematics that makes them useful. This page combines a searchable collection of 60 external chemistry resources with original worked examples on moles, titrations, gas calculations, enthalpy and pH.

This is a revision hub, not a single downloadable textbook. The linked PDFs are Chemrevise resources hosted by their original publisher. They cover physical, inorganic and organic chemistry, spectroscopy and synthesis. Check your exam board, qualification code and exam year before treating any set of notes as your complete syllabus.

A-level chemistry calculation routes: n equals mass divided by molar mass, n equals concentration times volume, and heat equals mass times specific heat capacity times temperature change. — Build the calculation from quantities and units, rather than choosing a formula from memory alone.

How to use these notes for your course

Match the specification. “A-level chemistry” covers several qualifications. AQA 7405, Pearson Edexcel 9CH0, OCR A H432 and Cambridge International 9701 have their own content and assessment requirements. Topic overlap does not make their courses or papers interchangeable.
Choose one small learning goal. For example, “find concentration from a titration” is more useful for one study session than “revise physical chemistry”. Use the search or a section filter to find the relevant note.
Work before reading the answer. Write the equation, label the data and attempt a question. Read the notes to repair the step you could not explain, then close them and repeat that step unaided.
Return to your board’s questions. Check wording, required practical skills, data-booklet conventions and mark-scheme expectations. Record whether each error came from chemistry, arithmetic, units or interpretation.

The dates printed on resource cards are inherited publication labels. They do not certify alignment with your current exam session. Two different polymer PDFs are intentionally retained; use the title, source date and contents to choose the one you need.

Choose the calculation before touching the calculator

Mass → amount

n = m ÷ M

Amount n is measured in mol. Use mass m in grams with molar mass M in g mol⁻¹. Relative formula mass, M_r, is a ratio and has no unit; its numerical value gives the molar mass in g mol⁻¹.

Solution → amount

n = cV

For concentration c in mol dm⁻³, volume V must be in dm³. Divide cm³ by 1000. The units cancel to mol. Do not use the same c symbol as a concentration in a calorimetry calculation: there it means specific heat capacity.

Reactant → product

moles → ratio → moles

Balance the chemical equation, calculate the known amount, and use its coefficients to get the unknown amount. Only then convert back to mass, concentration or gas volume. If both reactant amounts are supplied, first check which limits the reaction.

Temperature → energy

q = mcΔT

Use compatible units: grams, J g⁻¹ K⁻¹ and a temperature change in K give joules. A temperature difference has the same numerical value in °C and K. An absolute temperature in a gas calculation must instead be converted to kelvin.

Five worked physical-chemistry examples

1. How much carbon dioxide can a mass of carbonate make?

Calculate the theoretical mass of CO₂ from complete decomposition of 10.0 g CaCO₃. Use M(CaCO₃) = 100.0 g mol⁻¹ and M(CO₂) = 44.0 g mol⁻¹.

CaCO₃(s) → CaO(s) + CO₂(g)

n(CaCO₃) = 10.0 ÷ 100.0 = 0.100 mol
The coefficients give a 1 : 1 mole ratio, so n(CO₂) = 0.100 mol
m(CO₂) = 0.100 × 44.0 = 4.40 g

Check: the remaining 5.60 g is CaO in this ideal calculation, so the product masses total 10.0 g. A 1 : 1 mole ratio never meant equal masses. This is a theoretical yield, not a promise of the mass collected in a practical.

Mole bridge: 10.0 grams of calcium carbonate divided by 100.0 grams per mole gives 0.100 mole. A one-to-one ratio gives 0.100 mole carbon dioxide; multiplying by 44.0 gives 4.40 grams. — Convert to moles before crossing a balanced equation’s ratio.

2. A titration where the ratio is not 1 : 1

25.00 cm³ of sulfuric acid reacts completely with 20.00 cm³ of 0.1000 mol dm⁻³ sodium hydroxide. Find the acid concentration at full neutralisation.

H₂SO₄ + 2NaOH → Na₂SO₄ + 2H₂O

V(NaOH) = 20.00 ÷ 1000 = 0.02000 dm³
n(NaOH) = 0.1000 × 0.02000 = 0.002000 mol
One mole of acid reacts with two moles of NaOH: n(acid) = 0.002000 ÷ 2 = 0.001000 mol
c(acid) = 0.001000 ÷ 0.02500 = 0.04000 mol dm⁻³

Common wrong answer: 0.08000 mol dm⁻³ ignores the coefficient 2. The equality c_acidV_acid = c_baseV_base does not apply here. The correct relationship is 2c_acidV_acid = c_baseV_base. For a fuller equation check, use the chemical reaction calculator.

3. A warming solution and a negative enthalpy change

At constant pressure, a reaction warms 100.0 g of solution by 5.00 K. Take its specific heat capacity as 4.18 J g⁻¹ K⁻¹. If the reaction uses 0.0500 mol of the stated reacting substance, estimate the enthalpy change per mole of that substance.

q(solution) = 100.0 × 4.18 × 5.00 = +2090 J = +2.09 kJ
Assume no heat escapes and neglect heat absorbed by the cup: q(reaction) ≈ −2.09 kJ
ΔH ≈ −2.09 ÷ 0.0500 = −41.8 kJ mol⁻¹

The solution gains energy while the reaction releases it. Using a positive sign for the reaction would describe the opposite energy transfer. This estimate assumes a water-like specific heat capacity; a real calorimeter, heat loss and the actual solution composition can change the result. State which substance or reaction amount your “per mole” refers to.

The solution gains 2.09 kilojoules while the reaction loses approximately 2.09 kilojoules. Dividing by 0.0500 mole gives minus 41.8 kilojoules per mole at constant pressure under the stated no-heat-loss assumptions. — Match the sign to the system whose energy you are describing.

4. Gas volume: why the unit conversion matters

Estimate the volume of 0.100 mol of an ideal gas at 100 kPa and 298 K, using R = 8.314 J mol⁻¹ K⁻¹.

V = nRT ÷ p

Convert the pressure: 100 kPa = 100,000 Pa
V = (0.100 × 8.314 × 298) ÷ 100,000 = 0.002477572 m³
Multiply m³ by 1000: V ≈ 2.48 dm³

The values here are treated as three-significant-figure data. At 25 °C, T would be 298.15 K; 298 K is the temperature explicitly supplied in this question. A memorised molar gas volume belongs to particular conditions and is not a universal replacement for pV = nRT. Real gases can depart from ideal behaviour.

5. Strong-acid pH: use the right concentration

Estimate the pH of 0.0100 mol dm⁻³ hydrochloric acid using the dilute-solution approximation, complete dissociation and negligible contribution from water.

[H⁺] ≈ 0.0100 mol dm⁻³
pH ≈ −log₁₀(0.0100) = 2.00

pH has no unit. A tenfold dilution gives approximately 0.00100 mol dm⁻³ H⁺ and pH 3.00 under the same assumptions; doubling pH does not mean halving acidity. For a weak acid, [H⁺] is generally smaller than the formal acid concentration and an equilibrium calculation is needed. Very dilute or concentrated solutions need further care. The pH calculator and method guide explains the models and their limits.

Six questions to try before opening the answers

Use the values supplied here. These are original practice questions, not official exam-board questions. Write at least one line of working and a unit where appropriate.

1. How many moles are in 5.85 g NaCl, if M = 58.5 g mol⁻¹?

n = 5.85 ÷ 58.5 = 0.100 mol. Dividing g by g mol⁻¹ leaves mol.

2. Find the moles in 35.0 cm³ of 0.200 mol dm⁻³ solution

V = 35.0 ÷ 1000 = 0.0350 dm³; n = 0.200 × 0.0350 = 0.00700 mol, or 7.00 × 10⁻³ mol. An answer of 7.00 mol missed the volume conversion.

3. For 2Mg + O₂ → 2MgO, how many moles of O₂ react with 0.120 mol Mg?

The Mg : O₂ ratio is 2 : 1, so n(O₂) = 0.120 ÷ 2 = 0.0600 mol. Complete reaction also produces 0.120 mol MgO.

4. A 50.0 g solution warms by 4.00 K. Use c = 4.18 J g⁻¹ K⁻¹. Find q for the solution

q = 50.0 × 4.18 × 4.00 = +836 J, or +0.836 kJ. This is the solution’s heat gain. The corresponding reaction heat is approximately −836 J only under the no-loss assumptions.

5. Find ideal-gas moles in 2.00 dm³ at 100 kPa and 300 K. Use R = 8.314

V = 0.00200 m³ and p = 100,000 Pa. n = pV ÷ RT = 200 ÷ (8.314 × 300) = 0.080186… mol ≈ 0.0802 mol, treating the data as three significant figures.

6. If [H⁺] = 1.00 × 10⁻⁴ mol dm⁻³, what is the approximate pH?

pH ≈ −log₁₀(10⁻⁴) = 4.00 using the concentration approximation. Relative to 1.00 × 10⁻³ mol dm⁻³, the hydrogen-ion concentration is ten times smaller and the pH is one unit higher.

If powers of ten are causing mistakes, review the scientific notation examples before repeating questions 2, 5 and 6.

Frequently asked questions

What is included on this A-Level Physical Chemistry Textbook page?

There are 60 original resource entries across five chemistry sections, plus the worked examples and practice above. Physical chemistry contains 31 entries, inorganic 10, organic 16, spectroscopy 2 and synthetic routes 1. The collection includes notes beyond physical chemistry; it is not one complete textbook or an exam-board-endorsed course.

How do I open the PDF notes on this page?

Use “Open PDF” for the in-page viewer, then Close or Escape to return to the resource. “Open source” opens the original file in a new tab. If your device cannot display an embedded PDF, the source link is the fallback. Browser download controls depend on your device and the publisher’s response.

Can I use this page for topic-by-topic A-Level chemistry revision?

Yes. Combine one section filter with a search word, such as “enthalpy” or “bonding”. The count shows how many resources match both choices. Clear search and filters to start again. The notes supplement your teacher’s plan, board specification, practical work and exam questions.

Are these files hosted on He Loves Math?

No. The notes stay on Chemrevise’s website; their authors retain their rights. HeLovesMath provides an organised reference collection and original teaching material here. Access and versions can change, so a successful link check is not a guarantee of future availability.

Which mistake should I fix first in a chemistry calculation?

Check the equation and units before revising the arithmetic. The wrong mole ratio, cm³ used as dm³, kPa used as Pa, or joules reported as kilojoules can overwhelm otherwise correct calculator work. For an unexplained negative result, ask whether the sign is meaningful, as in enthalpy, or impossible for the quantity, as for an amount of substance.

Sources & References

The worked examples and practice above are original HeLovesMath teaching material. The following specifications support the topic scope and conventions; the searchable PDF collection below is credited to Chemrevise.

AQA A-level Chemistry 7405: physical chemistry specification — Official scope for moles, solution concentration, ideal gas calculations, calorimetry and pH; identifies qualification 7405.
Pearson Edexcel A-level Chemistry 9CH0 specification — Official specification, Issue 3, February 2024: identifies 9CH0 and supports quantity/units, stoichiometry, calorimetry assumptions and pH coverage.
OCR A-level Chemistry A H432 — Official qualification overview identifies A-level code H432 and provides the current specification and assessment routes.
Cambridge International AS & A Level Chemistry 9701 — Official qualification overview identifies 9701 and provides syllabus files by exam year, supporting the instruction to check the learner’s board and session.
OpenStax Chemistry 2e: calorimetry — Explains the system/surroundings distinction, opposite solution/reaction heat signs and calorimetry heat-transfer assumptions.

Search the Chemrevise PDF resource collection

60 resources across 5 sections. All 60 original PDF destinations returned a PDF response in the October 4, 2026 link check. That check confirms the response and PDF signature, not a full review of every file or its curriculum alignment. Files remain on the publisher’s site; follow its reuse terms.

Search A-Level chemistry resources

60 of 60 resources shown.

Physical Chemistry

Build the quantitative and conceptual foundation of A-Level chemistry with calculations, atomic structure, bonding, energetics, kinetics, equilibria and redox.

Calculations

Balancing equations

Physical Chemistry · PDF · Chemrevise

Original listing: Core stoichiometry and equation balancing.

A-Level Chemistry Notes & Physical Chemistry Practice

How to use these notes for your course

Choose the calculation before touching the calculator

Mass → amount

Solution → amount

Reactant → product

Temperature → energy

Five worked physical-chemistry examples

1. How much carbon dioxide can a mass of carbonate make?

2. A titration where the ratio is not 1 : 1

3. A warming solution and a negative enthalpy change

4. Gas volume: why the unit conversion matters

5. Strong-acid pH: use the right concentration

Six questions to try before opening the answers

Frequently asked questions

Sources & References

Search the Chemrevise PDF resource collection

Physical Chemistry

Calculations

Balancing equations

1.21 moles and formulae

1.22 concentrations and solutions

1.23 gas calculations

1.24 calculations and chemical reactions

1.25 titrations

Atomic Structure

2.11 atomic structure and mass spectrometry

2.12 electronic structure

2.13 ionisation energies

Bonding

2.20 introduction to bonding

2.21 ionic bonding

2.22 covalent bonding

2.23 metallic bonding

2.24 shapes of molecules

2.25 intermediate bonding

2.26 intermolecular bonding

2.27 structure of solid crystals

Energetics

3.11 introduction enthalpy change

3.12 Hesses law

3.13 calorimetry

3.14 bond enthalpies

3.15 Born Haber Cycle

3.16 Entropy and Gibbs Energy

3.17 Enthalpies of Solution

Kinetics

4.1 reaction kinetics

Equilibria

4.2 equilibria

Acid-base Equilibria

4.30 acid bases and salts

4.35 acid base equilibria

Redox

4.40 redox

4.45 electrolysis

Redox Equilibria

4.50 redox equilibria

Inorganic Chemistry

Periodicity

5.1 periodicity

Group 2

5.2 group 2

Group 7: The halogens

5.3 group 7

Metal Extraction

5.4 metal extraction

Transition Metals

5.51 Introduction to transition metals

5.52 complex ions

5.53 colour in complex ions

5.54 chemistry V Mn Cu Co Cr Ag

5.55 Catalysis by transition metals

5.56 reactions of aqueous transition metal ions

Organic Chemistry

Organic Chemistry Core Topics

6.1 organic naming

6.1.5 isomerism

6.2 alkanes

6.3 alkenes