1. The lattice enthalpy for magnesium oxide is -3850 kJ mol^-1.

The energy needed to break up 0.1 mol MgO into gaseous ions at 298K is:

2. Which of these factors can make it hard to recycle polymeric materials from domestic waste:

(i) much plastic waste consists of containers which have a very low density,

(ii) it is hard for householders to distinguish one plastic from another

(iii) the presence of pigments and fillers often contaminates the pure polymers

(iv) polymers are so similar that no automatic methods of separation are practicable.

3. How any moles of aqueous sodium hydroxide react with 2 mol of ethanedioic acid?

4. Calculate the mass of sodium ethanoate salt ( Mr of 82 ) that would need to be added to 50.0 cm³ of 0.100 mol dm^-3 ethanoic acid solution to produce a pH of 4.54

The acid dissociation constant, Ka, for ethanoic acid is 1.70 x 10^-5 mol dm^-3

5. Why does the term [H₂O_(l)]not appear in the expression for K_a for methanoic acid?

The concentration of [H₂O_(l)]= 1.0

6. Which first-row d-block metal forms hydrated ions in the +3 state which undergo a ligand exchange reaction to form a deep red complex ion with thiocyanate ions, SCN^-.

7. In which of these complexes is the oxidation state of the metal +3?

(i) [Fe(H₂O)₅SCN]²⁺

(ii) [CoCl₄]^2-

(iii) [Cr(H₂O)₄Cl₂]⁺

(iv) [Ag(S₂O₃)₂]^2-

8. Which of these compounds can exist in two enantiomeric forms?

(i) 2-methylbutan-1-ol,

(ii) 2-bromo-1-chlorobutane,

(iii) 2-chloropentane,

(iv) 1-chlorobutane

9. Calculate the pH of a solution produced when 28.0 cm³ of 0.100 mol dm^-3 potassium hydroxide solution has been added to 94.0cm³ of 0.100 mol dm^-3 hydrocyanic acid solution.

The acid dissociation constant, Ka, for hydrocyanic acid is 1.70 x 10^-5 mol dm^-3

10. Ethanoic acid is a weak acid with a Ka value of 1.70 x 10^-5 mol dm^-3

Calculate the pH of a solution of ethanoic acid when it is in a concentration of 0.100 mol dm^-3