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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 2 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 1.6 mol and has stated molar mass 133 g/mol. Find its mass. Round to 3 decimal places if needed. Answer in g.
g
2General chemistryFor the abstract reaction A + 2B → C, 45 mol A and 2 mol B are available. Assume complete consumption of the limiting reactant. Find the maximum amount of C. Round to 3 decimal places if needed. Answer in mol.
mol
3Chemical reactionsBalance this equation using the smallest whole-number coefficients: __ Zn + __ HCl → __ ZnCl₂ + __ H₂. What is the coefficient of ZnCl₂?
4Chemical reactionsIn a sealed container, a 20.2 g sample of a compound decomposes completely into 12.5 g of a gas and one solid product. What is the mass of the solid?
g
5Acids, bases & pHSolution X has pH 4 and solution Y has pH 11. Which is more basic?
6Acids, bases & pHSolution X has pH 1 and solution Y has pH 8. Which is more acidic?
7Analytical chemistryA supplied valid-range calibration is S = 7c + 0.1. The signal is 2.4. Find c in the calibration's arbitrary concentration units. Round to 3 decimal places if needed.
8Analytical chemistryThe theoretical dry pure product mass is 93 g; the actual dry pure product mass is 79 g. Find percentage yield. Round to 3 decimal places if needed. Answer in %.
%
9Physical chemistryAn ideal gas has initial pressure 59 kPa and volume 4.8 L. At fixed amount and temperature its volume becomes 3.8 L. Find the new pressure. Round to 3 decimal places if needed. Answer in kPa.
kPa
10Physical chemistryUse PV = nRT and R = 8.314 kPa·L/(mol·K). Find the ideal-gas volume for 0.5 mol at 344 K and 108 kPa. Round to 3 decimal places if needed. Answer in L.
L
11Organic chemistryA hydrocarbon molecule contains 1 carbon atoms. In a complete-combustion model, all its carbon forms CO₂. How many moles of CO₂ come from 0.9 mol hydrocarbon? Round to 3 decimal places if needed. Answer in mol.
mol
12Organic chemistryIgnoring end groups in a supplied model, a polymer chain has 224 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
13BiochemistryA simple unbranched, noncyclic peptide contains 141 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.

15Organic chemistry (Grade 11)Which is conventionally treated as an inorganic carbon compound?
16Analytical chemistry (Grade 11)A model solution contains 36 g solute and 303 g solvent. Find the solute mass percentage. Round to 3 decimal places if needed. Answer in %.
%