In all of the problems involving calculations, you must show your working and use dimensional analysis in all your answers.
The following abbreviations have been used: dp = decimal places, sf = significant figures.
Question 1
You are presented with 20 mL of an aqueous HCI solution in a conical flask. By titration (using a pH meter), 8 mL of 0.4 M NaOH is needed to neutralise the solution.
(a) What pH reading will the neutralised solution give?
(b) What is the molar concentration of the aqueous HCI solution (to 2 dp)?
Question 2
(a) What is Valence Shell Electron Pair Repulsion theory and what is it used to explain?
(b) What are degenerate orbitals? [1 mark]
(c) Draw energy level diagrams representing the electronic configurations of silicon (Si) atom and the bromide anion (Br)
Question 3 Chemical reactions proceed via a variety of different mechanisms.
Explain in detail the steps involved in a free radical reaction mechanism and give an example of a reaction that proceeds via this mechanism.
Question 4 For a 0.25 M aqueous solution of nitric acid (HNO3) calculate the following to 3 sf:-
(a) pH [2 marks] (b) [HO]
Question 5
Draw the skeletal structures and give the IUPAC names for all the possible alcohol isomers corresponding to the molecular formula C5H120. Show how many of these structures are chiral by marking the asymmetric carbon atoms?
