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Grade 9 · Chemistry

Grade 9 Chemistry diagnostic

16 questions on general chemistry, chemical reactions, acids, bases & ph, inorganic chemistry, analytical chemistry, physical chemistry and organic chemistry, plus 2 from Grade 8. 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 chemistryA model sample has mass 5 g and stated molar mass 22 g/mol. Find its amount. Round to 3 decimal places if needed. Answer in mol.
mol
2General chemistryA sample contains 1 mol and has stated molar mass 29 g/mol. Find its mass. Round to 3 decimal places if needed. Answer in g.
g
3Chemical reactionsBalance this equation using the smallest whole-number coefficients: __ NaHCO₃ → __ Na₂CO₃ + __ H₂O + __ CO₂. What is the coefficient of CO₂?
4Chemical reactionsIn a sealed container, a 21.4 g sample of a compound decomposes completely into 3 g of a gas and one solid product. What is the mass of the solid?
g
5Acids, bases & pHHow many times greater is the hydrogen-ion concentration in a solution of pH 9 than in a solution of pH 13?
6Acids, bases & pHSolution X has pH 9 and solution Y has pH 8. Which is more basic?
7Inorganic chemistryWhat is the total charge number of two Al³⁺ ions?
8Inorganic chemistryWhy do main-group elements in one group often react in related ways?
9Analytical 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
10Analytical chemistryA model solution contains 54 g solute and 70 g solvent. Find the solute mass percentage. Round to 3 decimal places if needed. Answer in %.
%
11Physical chemistryA faster reaction necessarily has a more negative ΔH. Is that valid?
12Physical chemistryWhich sign normally describes ΔH for an exothermic reaction?
13Organic chemistryAn acyclic saturated hydrocarbon has 16 carbon atoms. How many hydrogen atoms does its molecular formula contain? Round to 3 decimal places if needed.
14Organic chemistryA stated repeat unit has two carbon atoms. How many carbons are in 30 such repeat units, ignoring end groups?

From Grade 8

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

15General chemistry (Grade 8)Which description fits a compound?
16General chemistry (Grade 8)O₂ contains only oxygen atoms. Is it an element or a compound?