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Grade 12 · Chemistry

Grade 12 Chemistry diagnostic

16 questions on general chemistry, chemical reactions, acids, bases & ph, analytical chemistry, physical chemistry, organic chemistry and biochemistry, plus 2 from Grade 11. Answer what you can, then check your answers to see which topics are secure and what to practise next.

16 questions7 topicsAbout 20 minutesSet 3 of 5

Skip a question if you do not know the answer. It is better than guessing, because it shows what to practise.

1General chemistryWhich is the correct formula for the ionic compound formed from aluminium (Al) and iodine (I)?
2General chemistryA sample contains 1.9 mol and has stated molar mass 97 g/mol. Find its mass. Round to 3 decimal places if needed. Answer in g.
g
3Chemical reactionsIn a sealed container, 8.5 g of substance A reacts completely with 9.1 g of substance B. The only product is substance C. What mass of C forms?
g
4Chemical reactionsClassify this reaction: N₂ + 3 H₂ → 2 NH₃
5Acids, bases & pHSolution X has pH 1 and solution Y has pH 3. Which is more acidic?
6Acids, bases & pHSolution X has pH 4 and solution Y has pH 11. Which is more acidic?
7Analytical chemistryMeasured from the same origin, a spot travels 8 mm and the solvent front 87 mm. Find Rf. Round to 3 decimal places if needed.
8Analytical chemistryAn aqueous solution has concentration 0.2 mol/L. A model aliquot has volume 374 mL. Find the solute amount. Round to 3 decimal places if needed. Answer in mol.
mol
9Physical chemistryFor one reaction as written, a bond model requires 1133 kJ/mol to break bonds and releases 838 kJ/mol on forming bonds. Estimate ΔH. Round to 3 decimal places if needed. Answer in kJ/mol.
kJ/mol
10Physical chemistryFor A ⇌ B, use Kc = [B]/[A]. Equilibrium concentrations are [A] = 3.7 and [B] = 4.4 mol/L. Find Kc. Round to 3 decimal places if needed.
11Organic chemistryIgnoring end groups in a supplied model, a polymer chain has 500 repeat units, each contributing 28 g/mol to the chain molar mass. Estimate that mass. Round to 3 decimal places if needed. Answer in g/mol.
g/mol
12Organic chemistryA hydrocarbon molecule contains 10 carbon atoms. In a complete-combustion model, all its carbon forms CO₂. How many moles of CO₂ come from 2.7 mol hydrocarbon? Round to 3 decimal places if needed. Answer in mol.
mol
13BiochemistryA simple unbranched, noncyclic peptide contains 135 amino-acid residues. How many peptide links connect adjacent residues? Round to 3 decimal places if needed.
14BiochemistryWhere are phospholipid tails mainly found in a bilayer?

From Grade 11

These questions check skills from the grade below, so gaps can be spotted early.

15Analytical chemistry (Grade 11)A model solution contains 58 g solute and 374 g solvent. Find the solute mass percentage. Round to 3 decimal places if needed. Answer in %.
%
16Organic chemistry (Grade 11)In ethene CH₂=CH₂, what is the bond order of the bond between the carbons?