Paper 1: Advanced Inorganic and Physical Chemistry

Which ion has the same number of electrons as a neon atom?

Copper consists of 69.1% ⁶³Cu and 30.9% ⁶⁵Cu. Calculate the relative atomic mass of copper to 1 decimal place.

Explain why there is a large increase between the second and third ionisation energies of magnesium.

Which substance has the highest boiling temperature?

Use electron-pair repulsion theory to predict the shape and bond angle of the NH₄⁺ ion and the H₂O molecule.

Explain why graphite conducts electricity but diamond does not.

Write the ionic half-equations and the overall equation for the reaction of chlorine with iodide ions.

Give the oxidation number of manganese in MnO₄⁻ and in MnO₂.

Describe and explain the trend in thermal stability of the Group 2 carbonates.

Describe the observations when concentrated sulfuric acid is added to solid sodium iodide and explain why they differ from those with sodium chloride.

0.85 g of a volatile liquid was vaporised at 373 K and 101 kPa. The vapour occupied 300 cm³. Calculate the molar mass.

1.20 g of brass was dissolved in nitric acid, neutralised and made up to 250 cm³. 25.0 cm³ portions were added to excess KI. The iodine released needed 13.20 cm³ of 0.100 mol dm⁻³ sodium thiosulfate. 2Cu²⁺ + 4I⁻ → 2CuI + I₂ I₂ + 2S₂O₃²⁻ → 2I⁻ + S₄O₆²⁻ Calculate the percentage by mass of copper in the brass.

Excess zinc was added to 25.0 cm³ of 0.200 mol dm⁻³ copper(II) sulfate. The temperature rose by 10.4 °C. Calculate ΔH for Zn + Cu²⁺ → Zn²⁺ + Cu. (Specific heat capacity of the solution = 4.18 J g⁻¹ °C⁻¹; density of the solution = 1.00 g cm⁻³.)

Calculate the lattice energy of magnesium oxide. ΔfH(MgO) −602; atomisation Mg +148; 1st IE Mg +738; 2nd IE Mg +1451; atomisation O +249; 1st EA O −141; 2nd EA O +798 (all kJ mol⁻¹).

Explain why the second electron affinity of oxygen is endothermic.

For CaCO₃(s) → CaO(s) + CO₂(g), ΔH = +178 kJ mol⁻¹ and ΔS(system) = +161 J K⁻¹ mol⁻¹. Calculate ΔS(surroundings) at 298 K and ΔS(total), and state whether the reaction is feasible at 298 K.

1.00 mol of ethanoic acid and 1.00 mol of ethanol were mixed with a little acid catalyst. At equilibrium 0.67 mol of ethyl ethanoate was present. Calculate Kc.

Explain why adding more ethanol increases the yield of ester but does not change Kc.

Calculate the pH of 0.20 mol dm⁻³ propanoic acid (Ka = 1.35 × 10⁻⁵ mol dm⁻³).

A buffer contains 0.20 mol dm⁻³ propanoic acid and 0.30 mol dm⁻³ sodium propanoate. Calculate its pH.

Explain how this buffer resists changes in pH when small amounts of acid or alkali are added, and why it would not work after large additions.

Calculate E°cell for a cell made from Ag⁺/Ag (+0.80 V) and Fe²⁺/Fe (−0.44 V), and write the overall cell reaction.

Explain why a reaction with a positive E°cell may not be observed in practice.

Explain why [Cu(H₂O)₆]²⁺ is coloured but [Zn(H₂O)₆]²⁺ is colourless.

Write an equation for the reaction of [Co(H₂O)₆]²⁺ with excess concentrated hydrochloric acid and state the colour change.

Explain how Fe²⁺ ions catalyse the reaction between peroxodisulfate and iodide ions.

Explain the trend in melting temperatures across Period 3 from sodium to argon.