Paper 1: Periodic table, elements and physical chemistry

How many neutrons are in one ⁵⁶Fe³⁺ ion?

How many moles are in 4.00 g of NaOH?

Which element has the highest first ionisation energy?

What is the shape of an SF₆ molecule?

What is the oxidation number of chromium in Cr₂O₇²⁻?

Which Group 2 hydroxide is the most soluble in water?

A halide gives a cream precipitate with AgNO₃(aq) that dissolves in concentrated but not dilute ammonia. The halide is:

The temperature of an exothermic equilibrium is increased. What happens to Kc?

What are the units of Kc for N₂(g) + 3H₂(g) ⇌ 2NH₃(g)?

What is the pH of 0.010 mol dm⁻³ HCl(aq)?

What is the value of Kw at 298 K?

Which ion has the electron configuration [Ar]3d⁵?

Which change has the most positive entropy change?

rate = k[A]²[B]. What are the units of k?

Which ion gives a blue precipitate with NaOH(aq)?

25.0 cm³ of sodium carbonate solution needed 23.50 cm³ of 0.150 mol dm⁻³ hydrochloric acid for neutralisation. Na₂CO₃ + 2HCl → 2NaCl + H₂O + CO₂ Calculate the concentration of the sodium carbonate solution.

Calculate the volume of CO₂, in cm³ at RTP, released when 0.500 g of CaCO₃ reacts completely with excess acid.

Calculate the atom economy for making CaO by heating CaCO₃, and suggest how the process could be made more sustainable.

Draw a dot-and-cross diagram for NH₃ and explain why its bond angle is 107°.

Explain why water has a higher boiling point than hydrogen sulfide, and why ice is less dense than liquid water.

Explain why the first ionisation energy decreases from Mg to Al and from P to S.

Calcium reacts with water. Write an equation, give two observations and estimate the pH of the resulting solution.

Chlorine reacts with cold dilute sodium hydroxide to make bleach. Write the equation, give the oxidation numbers of chlorine and explain why this is disproportionation.

Use average bond enthalpies to calculate ΔcH of methane. CH₄ + 2O₂ → CO₂ + 2H₂O C–H 413, O=O 498, C=O 805, O–H 464 (kJ mol⁻¹)

Explain, with reference to the Boltzmann distribution, how a catalyst increases the rate of a reaction.

0.500 mol H₂ and 0.500 mol I₂ were heated in a sealed 2.00 dm³ vessel. At equilibrium 0.780 mol HI was present. H₂(g) + I₂(g) ⇌ 2HI(g) Calculate Kc.

For N₂O₄(g) ⇌ 2NO₂(g) at equilibrium the total pressure is 200 kPa and the mole fraction of NO₂ is 0.40. Calculate Kp.

The table shows initial rates for 2A + B → products.

Exp	[A] / mol dm⁻³	[B] / mol dm⁻³	Rate / mol dm⁻³ s⁻¹
1	0.10	0.10	2.0 × 10⁻⁴
2	0.20	0.10	8.0 × 10⁻⁴
3	0.10	0.30	6.0 × 10⁻⁴

Determine the rate equation and calculate the rate constant with units.

Calculate the pH of 0.0250 mol dm⁻³ Ba(OH)₂(aq).

Calculate the pH of 0.100 mol dm⁻³ ethanoic acid (Ka = 1.75 × 10⁻⁵ mol dm⁻³), and state one approximation you made.

10.0 cm³ of 0.100 mol dm⁻³ NaOH is added to 25.0 cm³ of 0.100 mol dm⁻³ ethanoic acid. Calculate the pH of the buffer formed.

Calculate the lattice enthalpy of potassium chloride. ΔfH(KCl) −437; atomisation K +89; 1st IE K +419; atomisation Cl +122; 1st EA Cl −349 (kJ mol⁻¹)

The enthalpies of hydration of K⁺ and Cl⁻ are −322 and −378 kJ mol⁻¹. Calculate the enthalpy change of solution of KCl.

ΔS for dissolving KCl is +75 J K⁻¹ mol⁻¹. Use ΔG to show that KCl dissolves at 298 K even though the process is endothermic, and explain the role of entropy.

10.0 cm³ of bleach was diluted to 250 cm³. 25.0 cm³ of this was added to excess acidified KI. The iodine released needed 18.60 cm³ of 0.0500 mol dm⁻³ Na₂S₂O₃. ClO⁻ + 2I⁻ + 2H⁺ → Cl⁻ + I₂ + H₂O I₂ + 2S₂O₃²⁻ → 2I⁻ + S₄O₆²⁻ Calculate the concentration of ClO⁻ in the original bleach.

Write the half-equations at each electrode and the overall equation for an alkaline hydrogen–oxygen fuel cell.

Describe the stereoisomerism shown by transition metal complexes, using [Pt(NH₃)₂Cl₂] and [Ni(NH₂CH₂CH₂NH₂)₃]²⁺ as examples, and explain how cisplatin acts as an anticancer drug.

Describe what you would see when aqueous sodium hydroxide is added dropwise and then in excess to a solution containing Cr³⁺(aq), and give the formula of the final complex. State what forms instead with excess aqueous ammonia.