Edexcel A Level Chemistry Paper 1: Advanced Inorganic and Physical Chemistry November 2020 question paper 9CH0/01

Which equation shows the third ionisation energy of aluminium?

Which element in this table is in Group 2?

		Ionisation energy / kJ mol	1
Element	First	Second	Third	Fourth
W	1086	2353	4621	6223
X	653	1592	2987	4740
Y	590	1145	4912	6474
Z	496	4563	6913	9544

The graph shows the first ionisation energies (I E) of eight successive elements from the first 20 elements in the Periodic Table.

Which letter represents the first ionisation energy of oxygen?

Give the formula of a stable ion that is isoelectronic with the magnesium ion, Mg².

A student stated that ‘the elements scandium and zinc are d-block elements but are not transition metals’.

Discuss this statement, using appropriate electronic configurations to support your answer.

This question is about acids and bases.

What is the order of decreasing pH for 0.100 mol dm³ solutions of these three acids?

A solution of methanoic acid, HCOOH, has a concentration of 0.240 mol dm³ and a pH of 2.20.

Calculate the value of pK_a for methanoic acid.

Which of these mixtures would form a buffer solution with a pH below 7?

Bromothymol blue, methyl orange and phenolphthalein are indicators used in titrations.

Which, if any, of these indicators could be used for a titration of ammonia, NH₃(aq), with ethanoic acid, CH₃COOH(aq)?

This question is about transition metals and transition metal complexes.

Describe the bonding in the element chromium and use your answer to justify why it has such a high melting temperature.

You may find it helpful to draw a labelled diagram.

When chromium(III) sulfate dissolves in water, a green solution containing the [Cr(H₂O)₆]³ ion forms.

Give the shape of this complex ion.

Explain why the chromium complex ion is coloured.

The ligand ethylenediaminetetraacetate, EDTA⁴, has the structure shown.

When a solution of EDTA⁴ is added to a solution of [Cr(H₂O)₆]³ ions, a new complex ion is formed.

The equilibrium constant for this equilibrium is 2.51 10²³ dm³ mol⁻¹.

By considering the equilibrium for this reaction and changes in entropy, comment on the value of the equilibrium constant. No calculations are required.

Aqueous vanadium(II) chloride, VCl₂(aq), can be oxidised by bubbling gaseous chlorine, Cl₂(g), through the solution in the absence of air.

40.0 cm³ of 0.100 mol dm³ VCl₂ solution was oxidised by 144 cm³ of chlorine gas, at room temperature and pressure (r.t.p.). The chlorine was reduced to chloride ions, according to the half-equation

[Molar volume of a gas at r.t.p. 24.0 dm³ mol¹]

Use these data to calculate the final oxidation state of vanadium. You must show your working.

State the initial and final colours you would see as the chlorine bubbles through the aqueous vanadium(II) chloride, VCl₂(aq).

This question is about dissolving different compounds.

Which of these compounds is the most soluble in water?

*(c) The solubility of two compounds in different solvents was investigated. A summary of the findings is shown.

Explain the findings of the investigation by considering the interactions between the compounds and each of the solvents.

This question is about the chemistry of hydrated magnesium nitrate, Mg(NO₃)₂.xH₂O.

Group 2 nitrates decompose when heated.

State two observations you would see when hydrated magnesium nitrate is heated.

Explain the trend in thermal stability of Group 2 nitrates.

In an experiment, a sample of hydrated magnesium nitrate, Mg(NO₃)₂.xH₂O, with a mass of 0.765 g, was dissolved in water and reacted with an excess of sodium hydroxide solution, NaOH(aq). The precipitate of magnesium hydroxide, Mg(OH)₂, produced was removed and dried. The mass of the dried sample was 0.174 g.

Draw dot-and-cross diagrams for the ions in magnesium hydroxide. Show the outer electrons only.

Use the experimental data to calculate the value for x in the formula Mg(NO₃)₂.xH₂O. You must show all your working.

Prop-2-en-1-ol is an unsaturated alcohol with the structure shown.

A student planned to use bond enthalpy data to calculate a value for the enthalpy change of combustion of prop-2-en-1-ol.

When researching the bond enthalpy data, the student claimed that it was not necessary to find the value for the CC bond as they could use the value for a C – C bond and multiply it by two. Explain why the student is incorrect.

Calculate a value for the enthalpy of combustion of prop-2-en-1-ol using the data shown.

Bond	C−C	CC	C−O	CO	O−H	C−H	OO
Bond enthalpy / kJ mol1	347	612	358	805	464	413	498

Explain, in terms of entropy, why the combustion of prop-2-en-1-ol is always feasible in the gaseous state.

Chemists are researching a process to make ethanol and ethene directly from carbon dioxide and water.

	CO2(g)	H2O(l)	CH3CH2OH(l)	C2H4(g)	O2(g)
SO / J K1 mol1	213.6	69.9	160.7	219.5	205.0

Calculate ∆S^O_total for the reaction and hence determine whether the reaction is feasible under standard conditions.

A mixture of ethanoic acid, ethanol and a catalyst was left for several days to reach equilibrium.

The equilibrium constant, K_c, under these conditions, was 0.28.

Write the expression for the equilibrium constant, K_c.

The two O−C−H bond angles, x and y, in the ester are approximately

The reaction often forms an equilibrium mixture.

Which could be the units for the equilibrium constant, K_p?

Describe what effect, if any, increasing the pressure would have on the equilibrium constant, K_p. Justify your answer.

Tablets containing potassium manganate(VII), KMnO₄, are dissolved in water forming an antiseptic solution to treat skin conditions. The manufacturers claim that each tablet contains 400 mg of KMnO₄.

To check the claim, the titration procedure outlined was carried out.

Five tablets were dissolved in distilled water to make 100.0 cm³ of solution. Some of the KMnO₄ solution was used to fill a burette. 25.0 cm³ of sodium ethanedioate solution, Na₂C₂O₄(aq), of concentration 0.200 mol dm³, was added to a conical flask and warmed. Sulfuric acid, of concentration 2 mol dm³, was also added to the conical flask. The KMnO₄ solution was added to the flask from the burette, until the end-point.

The equation for the reaction between MnO₄ ions from the KMnO₄ and C₂O₄² ions from the sodium ethanedioate solution is shown.

Give the colour change at the end-point of the titration.

Complete the dot-and-cross diagram for the ethanedioate ion. Show the outer electrons only.

Determine the oxidation number of carbon in the ethanedioate ion, C₂O₄².

Give the reason why sulfuric acid was also added to the conical flask.

This redox reaction could be used in an electrochemical cell.

The cell half-equations are

Write a cell diagram for this cell using the conventional representation.

The results of the titration are shown.

Complete the table.

The equation for the reaction between MnO₄ ions from the KMnO₄ and C₂O₄² ions from the sodium ethanedioate solution is shown.

Use this equation and your mean titre from (e)(i) to calculate the mass, in mg, of KMnO₄ in one tablet.

Give your answer to an appropriate number of significant figures.

A textbook suggested the conical flask should be heated during the titration, as the reaction between the MnO₄ ions and the C₂O₄² ions is slow.

Use these electrode potentials and your knowledge of homogeneous catalysis to deduce why the heating is very important at the start of the titration, but less important as the titration proceeds. Justify your answer. You may include equations in your justification.

Electrode system	EO / V
2CO2(g) 2e ⇌ C2O42(aq)	0.64
Mn3(aq) e– ⇌ Mn2+(aq)	1.49
MnO4(aq) 8H+(aq) 5e ⇌ Mn2+(aq) 4H2O(l)	1.51