Drill the stoichiometry, equilibrium and pH calculations free, find your weakest unit in a 23-minute test, then write free-response answers Mia marks point by point.
The only interactive course with a tutor that finds your weak spots and fixes them.
One payment in US dollars. Full refund within 14 days, for any reason.
24 stoichiometry, equilibrium and pH problems. Type a number: the page works the answer out again from the problem's own values and the constants on the equations sheet, then shows the full setup.
Stoichiometry, problem 1 of 8
Iron(III) oxide is reduced by carbon monoxide: Fe₂O₃(s) + 3CO(g) → 2Fe(s) + 3CO₂(g). What mass of iron, in grams, can be made from 50.0 g of Fe₂O₃?
15 questions across all nine units, no account. You get your score in each unit, the one to fix first, a short lesson on it and four fresh questions to check it worked.
Type your answer to a question in the exam's format. Mia marks every point, quotes the words that earned it and shows a full-credit answer.
Units are not worth the same: Properties of Substances and Mixtures is 18–22% of Section I, most other units 7–9%. Set your hours and how sure you are of each unit, and get a week-by-week plan to May 6.
The May 2027 exam: 60 multiple-choice questions in 90 minutes and 7 free-response questions in 105 minutes, on Thursday, May 6, 2027.
Moles, mass spectra, composition, electron configuration, PES and periodic trends.
7–9% of Section I
Bonds, ionic solids and metals, Lewis diagrams, formal charge and VSEPR.
7–9% of Section I
Intermolecular forces, gases, solutions, separation, spectroscopy and Beer-Lambert.
18–22% of Section I
Net ionic equations, stoichiometry, titration and the three reaction types.
7–9% of Section I
Rate laws, half-life, collisions, energy profiles, mechanisms and catalysts.
7–9% of Section I
Heat, calorimetry, phase changes, bond enthalpies and Hess's law.
7–9% of Section I
Q and K, ICE tables, Le Chatelier's principle and solubility equilibria.
7–9% of Section I
pH, weak acids and bases, titration curves, buffers and pKa.
11–15% of Section I
Entropy, Gibbs free energy, galvanic and electrolytic cells.
7–9% of Section I
| Category | Sample 1 | Sample 2 |
|---|---|---|
| 0 | 0 | 0 |
| 200 | 9.6 | 2.1 |
| 400 | 19.6 | 6.9 |
| 600 | 14.3 | 10.6 |
| 800 | 5.3 | 11.2 |
| 1000 | 1.1 | 8.9 |
| 1200 | 0.1 | 5.6 |
| 1400 | 0 | 2.9 |
| 1600 | 0 | 1.2 |
US$59one payment
Full refund within 14 days. Ask within 14 days of paying, for any reason. Our refund promise still applies after you start the course. The note under the pay button is about the separate legal right to cancel. Terms
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One payment. No sales tax is added. Access until October 31, 2027.
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