Exam-style practice (harder): Chemistry multiple choice quiz
14 questions. Pick an answer and you'll see why right away. Options are shuffled each attempt, and the review at the end links each missed question to the dot point to revise.
A solution calorimeter is calibrated by passing a current of 5.00 A at 4.20 V for 120 s, which raises the temperature by 1.60 °C. Then 0.0500 mol of a salt is dissolved in the calorimeter, and the temperature falls by 0.80 °C.
What is the enthalpy change for dissolving the salt?
A galvanic cell is made from a Zn(s)/Zn²⁺(aq) half-cell and a Cu(s)/Cu²⁺(aq) half-cell, connected by a wire and a KNO₃ salt bridge. Standard conditions apply.
Which statement is correct?
A current of 2.00 A is passed through copper(II) sulfate solution for 30.0 minutes, and copper is deposited at the cathode. F = 96 500 C mol⁻¹ and M(Cu) = 63.5 g mol⁻¹.
What mass of copper is deposited?
Use these standard reduction potentials:
Half-equation E° (V) Ag⁺(aq) + e⁻ ⇌ Ag(s) +0.80 Cu²⁺(aq) + 2e⁻ ⇌ Cu(s) +0.34 Pb²⁺(aq) + 2e⁻ ⇌ Pb(s) -0.13 Fe²⁺(aq) + 2e⁻ ⇌ Fe(s) -0.44 Which option gives a reaction predicted to occur spontaneously and the maximum voltage of a standard cell based on it?
0.80 mol of SO₂ and 0.50 mol of O₂ are placed in a sealed 2.0 L vessel and allowed to reach equilibrium at a constant temperature:
2SO₂(g) + O₂(g) ⇌ 2SO₃(g)
At equilibrium, the vessel contains 0.60 mol of SO₃. What is the value of the equilibrium constant, Kc?
A catalyst is added to a reaction mixture at constant temperature.
Which statement correctly describes the effect, in terms of the Maxwell-Boltzmann distribution of particle energies?
The reaction 2NO₂(g) ⇌ N₂O₄(g), ΔH = -57 kJ mol⁻¹, is at equilibrium in a sealed vessel. At time t a single change is made. There is no sudden jump in either concentration at time t; afterwards [NO₂] gradually increases and [N₂O₄] gradually decreases until a new equilibrium is reached.
Which change was made, and what was its effect on Kc?
How many structural isomers with the molecular formula C₄H₁₀O are alcohols?
Which sequence of reactions would produce ethyl ethanoate, using ethene as the only organic starting material?
A compound with the molecular formula C₄H₈O₂ has this ¹H NMR spectrum:
Chemical shift (ppm) Relative peak area Splitting 3.7 3 singlet 2.3 2 quartet 1.1 3 triplet Which compound is it?
10.00 mL of vinegar is diluted to 100.0 mL in a volumetric flask. 25.00 mL aliquots of the diluted solution are titrated with 0.100 M NaOH, giving an average titre of 20.00 mL.
What is the concentration of ethanoic acid in the original vinegar?
Caffeine in an energy drink is measured by HPLC. Caffeine standards gave these results, with a retention time of 4.2 minutes:
Caffeine (mg L⁻¹) 0 50 100 150 Peak area 0 1200 2400 3600 The drink was diluted 1 in 5 (one part drink to four parts water). The diluted drink gave a peak at 4.2 minutes with an area of 1800. Which statement is correct?
Two breads contain the same mass of starch per serve. The starch in bread X contains a higher proportion of amylose; the starch in bread Y contains a higher proportion of amylopectin.
Which bread is likely to have the lower glycaemic index (GI), and why?
Ethanol releases 29.6 kJ of energy per gram when burnt. A spirit burner heats 1.00 kg of water from 20.0 °C to 70.0 °C. Only 70.0% of the energy released by the burning ethanol is transferred to the water. The specific heat capacity of water is 4.18 J g⁻¹ °C⁻¹.
What mass of ethanol must be burnt?