Augment’s own questions for Chemistry, written in the style of IB exams, each with its markscheme. They are not past papers. One from each topic is below to try.
Every question has a markscheme.
The paper each question is written for, so you can practice one paper at a time.
Each topic in syllabus order, with its subtopics. Lines with notes link to them. Under each topic is one question to try, its markscheme folded until you open it.
Which is an assumption of the ideal gas model?
The answer is D.
The ideal gas model assumes that collisions are elastic (no loss of total kinetic energy), that the particles have negligible volume and that there are no intermolecular forces.
A describes a real gas. B confuses negligible volume with zero mass. C is wrong: the particles have a range of speeds; only the average kinetic energy is fixed by the temperature.
An atom of element X has the electron configuration 1s2 2s2 2p6 3s2 3p4.
Which ion does X form in its ionic compounds?
The answer is A.
X has six valence electrons (3s2 3p4), so it is a non-metal in group 16 (sulfur). It gains two electrons to reach the configuration of argon, forming X2−.
B assumes one electron is gained (group 17). C confuses non-metals with metals, which lose electrons. D would require the loss of all six valence electrons, which does not happen in simple ionic compounds.
What is the empirical formula of butane?
The answer is B.
The molecular formula of butane is C4H10; dividing by the highest common factor (2) gives the simplest whole-number ratio, C2H5.
A is the empirical formula of the alkenes. C is the molecular formula, not the simplest ratio. D is the condensed structural formula.
Butane, C4H10, is used as a fuel in portable gas stoves. What is the coefficient of oxygen when the equation for the complete combustion of one mole of butane is balanced?
The answer is C.
Oxygen atoms needed: 4 × 2 (in CO2) + 5 (in H2O) = 13 atoms = 6½ O2.
D (13) is the coefficient when two moles of butane are burned. A and B are the coefficients of CO2 and H2O.
Which statement is correct for a chemical system at dynamic equilibrium?
The answer is C.
At dynamic equilibrium both reactions continue at the same rate, so the concentrations stay constant.
A confuses constant with equal concentrations. B describes a static, not dynamic, state: both reactions are still happening. D would mean the composition is still changing.
Which species can act as a nucleophile?
The answer is C.
A nucleophile must have a lone pair of electrons that it can donate to form a new bond. The oxygen atom in H2O has two lone pairs, so water is a (neutral) nucleophile.
NO2+ and H+ are electron-pair acceptors (electrophiles). CH4 has no lone pairs: all of carbon's valence electrons are in C–H bonds.
A free account opens the whole question bank, keeps a record of what you have marked, and builds worksheets from the topics you pick.