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.
0.40 mol of N₂O₄ is placed in a sealed 2.0 L vessel and allowed to reach equilibrium at constant temperature:
N₂O₄(g) ⇌ 2NO₂(g)
At equilibrium, the vessel contains 0.20 mol of NO₂. What is the value of the equilibrium constant, K?
H₂(g) + I₂(g) ⇌ 2HI(g) is at equilibrium in a sealed vessel at constant temperature. A single change is made at 10 minutes.
Time [H₂] (mol/L) [I₂] (mol/L) [HI] (mol/L) 0 to 10 min 0.10 0.10 0.80 Just after 10 min 0.10 0.10 1.20 20 min onwards 0.14 0.14 1.12 Which statement correctly describes the change and its effect on K?
25.0 mL of 0.100 mol/L HCl is mixed with 20.0 mL of 0.100 mol/L NaOH at 25 °C.
What is the pH of the resulting solution?
Four mixtures are prepared at 25 °C. Which mixture is a buffer solution?
20.0 mL of a weak monoprotic acid, HA, is titrated with 0.100 mol/L NaOH at 25 °C.
Volume of NaOH added (mL) pH 0.0 2.9 10.0 4.8 20.0 (equivalence point) 8.7 30.0 12.3 Which statement is correct?
At 25 °C, the of lead(II) iodide, PbI₂, is .
What is the maximum concentration of Pb²⁺ that can remain in a solution in which [I⁻] = 0.010 mol/L?
Butanoic acid has the molecular formula C₄H₈O₂.
Which compound is a functional group isomer of butanoic acid?
Compound Molar mass (g/mol) Boiling point (°C) Butane 58 -1 Propanal 58 48 Propan-1-ol 60 97 Ethanoic acid 60 118 Which statement best explains why propan-1-ol boils about 50 °C higher than propanal?
A student burns 0.46 g of ethanol (molar mass 46.07 g/mol) under a can containing 200 g of water. The water temperature rises from 20.0 °C to 35.0 °C. The specific heat capacity of water is 4.18 J g⁻¹ K⁻¹.
What value for the molar heat of combustion of ethanol do these results give?
A colourless solution contains exactly one of the ions Pb²⁺, Ba²⁺ or Mg²⁺. A student adds dilute HCl to one sample: no precipitate forms. She adds dilute H₂SO₄ to a fresh sample: a white precipitate forms.
Which ion is present, and why was the HCl test done first?
A 2.00 g sample of fertiliser is dissolved in water and excess BaCl₂ solution is added. The BaSO₄ precipitate (molar mass 233.4 g/mol) is filtered, dried and weighed: 1.165 g. The molar mass of SO₄²⁻ is 96.07 g/mol.
What is the percentage by mass of sulfate in the fertiliser, and how would an incompletely dried precipitate affect this result?
The pH of hydrochloric acid and ethanoic acid solutions was measured at 25 °C.
Concentration (mol/L) pH of HCl pH of CH₃COOH 0.10 1.0 2.9 0.010 2.0 3.4 0.0010 3.0 3.9 Which conclusion is supported by the data?
A polymer is made from the monomers HOOC-C₆H₄-COOH (benzene-1,4-dicarboxylic acid) and HO-CH₂CH₂-OH (ethane-1,2-diol).
Which statement correctly describes the polymer and how it forms?
Copper in a water sample is measured by atomic absorption spectroscopy. The calibration standards gave:
Cu concentration (ppm) 0 2.0 4.0 6.0 8.0 Absorbance 0.000 0.110 0.220 0.330 0.440 10.0 mL of the water sample was diluted to 100.0 mL, and the diluted solution had an absorbance of 0.275. What is the copper concentration in the original water sample?