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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 4 of 5

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

1General chemistryA sample contains 1.3 mol and has stated molar mass 126 g/mol. Find its mass. Round to 3 decimal places if needed. Answer in g.
g
2General chemistryA model sample has mass 161 g and stated molar mass 142 g/mol. Find its amount. Round to 3 decimal places if needed. Answer in mol.
mol
3Chemical reactionsBalance this equation using the smallest whole-number coefficients: __ Fe₂O₃ + __ CO → __ Fe + __ CO₂. What is the coefficient of Fe₂O₃?
4Chemical reactionsIn a sealed container, 11.8 g of A and 18.2 g of B react until B is used up. 3.5 g of A is left over, and the only product is C. What mass of C forms?
g
5Acids, bases & pHSolution X has pH 2 and solution Y has pH 12. Which is more basic?
6Acids, bases & pHSolution X has pH 8 and solution Y has pH 12. Which is more basic?
7Analytical chemistryA 127 g sample is 92% desired substance by mass. Find the desired substance mass. Round to 3 decimal places if needed. Answer in g.
g
8Analytical chemistryMeasured from the same origin, a spot travels 21 mm and the solvent front 38 mm. Find Rf. Round to 3 decimal places if needed.
9Physical chemistryAt 25 °C, use the dilute model pH + pOH = 14. A solution has pH 2.7. Find pOH. Round to 3 decimal places if needed.
10Physical chemistryThe given standard reduction potentials are 0.86 V for the cathode and -0.85 V for the anode. Find E°cell. Round to 3 decimal places if needed. Answer in V.
V
11Organic chemistryIgnoring end groups in a supplied model, a polymer chain has 294 repeat units, each contributing 42 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 1 carbon atoms. In a complete-combustion model, all its carbon forms CO₂. How many moles of CO₂ come from 6.7 mol hydrocarbon? Round to 3 decimal places if needed. Answer in mol.
mol
13BiochemistryA simple unbranched, noncyclic peptide contains 121 amino-acid residues. How many peptide links connect adjacent residues? Round to 3 decimal places if needed.
14BiochemistryWhich feature is part of a nucleotide?

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 44 g solute and 187 g solvent. Find the solute mass percentage. Round to 3 decimal places if needed. Answer in %.
%
16Organic chemistry (Grade 11)How many carbon atoms are written in CH₃CH₂CH₃?