Edexcel A Level Chemistry Paper 1: Advanced Inorganic and Physical Chemistry June 2019 question paper 9CH0/01

1h 45m 90 marks

10 questions

Report a problem

Question

What is wrong?

Text or a picture is cut off or split Something on the paper is not here The text does not read properly The marks are wrong Something else

Goes to whoever maintains the question split. No account needed and nothing is published on this page.

This question is about atoms, molecules and ions.

(a)

The numbers of subatomic particles in an¹⁸O atom are

$Question 1, shown as an image$

(1)

Answer

(b)

The mass spectrum of a sample of bromine molecules with approximately equal proportions of the⁷⁹Br and⁸¹Br isotopes is

(1)

Answer

(c)

The total number of electrons in all the occupied p orbitals in a chloride ion, Cl^–, is

$Question 1, shown as an image$

(1)

Answer

(d)

Which of these isoelectronic ions has the largest ionic radius?

$Question 1, shown as an image$

(1)

Answer

This question is about some redox reactions of chlorine, bromine and iodine.

(a)

An excess of aqueous potassium bromide was added to chlorine water and the solution turned orange.

(a)(i)

Write an equation for this reaction. State symbols are not required.

(1)

Answer

(a)(ii)

Silver nitrate solution was added to the mixture in (a) and excess dilute ammonia solution was then added to the precipitate formed. Only some of the precipitate dissolved.

Deduce why only some of the precipitate dissolved.

(3)

Answer

(a)(iii)

Aqueous potassium bromide was added to aqueous iodine, instead of chlorine water. There was no reaction.

Give a reason why no reaction occurred.

(1)

Answer

(b)

Chlorine undergoes disproportionation when it reacts with hot aqueous sodium hydroxide solution.

(b)(i)

Complete the ionic equation for this reaction. State symbols are not required.

_........ Cl₂ +_........ OH^– maths symbol _........ Cl^– +_........ ClO₃^– +_........ H₂O

(1)

Answer

(b)(ii)

Explain, in terms of oxidation numbers, why this is a disproportionation reaction.

(2)

Answer

The standard molar enthalpy change of neutralisation is the enthalpy change when an acid and an alkali react under standard conditions to form one mole of water.

(a)

An experiment was carried out to determine the enthalpy change of neutralisation for the reaction between propanoic acid and sodium hydroxide.

The equation for this reaction is

CH₃CH₂COOH(aq) + NaOH(aq) maths symbol CH₃CH₂COO^–Na⁺(aq) + H₂O(l)

50.0 cm³ of sodium hydroxide solution, of concentration 1.00 mol dm^–3, was placed in a polystyrene cup. The initial temperature was measured.

(a)(i)

Which piece of equipment has the smallest measurement uncertainty for the measurement of 50.0 cm³ of sodium hydroxide solution?

(1)

Answer

(a)(ii)

50.0 cm³ of propanoic acid solution, of concentration 1.00 mol dm^–3, was added and thoroughly mixed with the sodium hydroxide solution in the polystyrene cup.

The maximum temperature rise was 6.5 °C.

Calculate the enthalpy change of neutralisation for propanoic acid, in kJ mol^–1, giving your answer to the nearest whole number.

[Assume density of the mixture = 1.00 g cm^–3, specific heat capacity of the mixture = 4.18 J g^–1 °C^–1]

(3)

Answer

(b)

Another experiment was carried out with a solution of ethanoic acid and sodium hydroxide solution of the same concentration.

(b)(i)

(1)

Answer

(b)(ii)

Explain why the data book value for the standard enthalpy change of neutralisation of ethanoic acid with sodium hydroxide is –55.2 kJ mol^–1 but the value for hydrochloric acid is –57.1 kJ mol^–1.

(2)

Answer

Thermal decomposition is the breaking down of a substance by heat.

(a)

An experiment was carried out to investigate the thermal decomposition of a metal nitrate using the apparatus shown.

(a)(i)

The glowing splint is used as a test for one of the gases given off in this experiment.

Identify this gas and the positive result of the test.

(1)

Answer

(a)(ii)

Give the name and appearance of the other gas given off in this experiment when a Group 2 nitrate is heated.

(1)

Answer

(a)(iii)

Write the equation for the decomposition if the Group 1 compound, sodium nitrate, was used in this experiment. State symbols are not required.

(1)

Answer

(a)(iv)

Describe the apparatus that would be used to compare the decomposition of metal carbonates. Include how the rate of decomposition would be compared.

(2)

Answer

(b)

Explain why magnesium carbonate decomposes much more readily on heating than barium carbonate.

(3)

Answer

This is a question about catalysis.

(a)

The reaction between iodide ions and peroxodisulfate ions is catalysed by iron(II) ions.

$Question 5, shown as an image$

(a)(i)

Give a reason why the reaction between iodide ions and peroxodisulfate ions has a high activation energy and is therefore very slow without a catalyst.

(1)

Answer

(a)(ii)

Explain, with the aid of two equations, how the iron(II) ions catalyse this reaction. State symbols are not required.

(3)

Answer

(b)

The oxidation of sulfate(IV) ions to sulfate(VI) ions is catalysed by cobalt(II) ions in acidic solution. The role of cobalt(II) ions is similar to that of iron(II) ions in (a).

$Question 5, shown as an image$

Deduce two ionic equations to show how cobalt(II) ions catalyse the reaction in acidic solution. State symbols are not required.

(2)

Answer

(c)

The rate of oxidation of ethanedioate ions by manganate(VII) ions starts slowly and then rapidly increases.

$Question 5, shown as an image$

What is the catalyst in this reaction?

$Question 5, shown as an image$

(1)

Answer

(d)

The trend in the strength of gaseous adsorption by three transition elements is

tungsten maths symbol platinum silver

Silver is not suitable as a replacement for platinum in a catalytic converter because the adsorption of gases is too weak to allow significant chemical reaction.

Give a possible reason why tungsten would also not be a suitable replacement for platinum in a catalytic converter. Refer to the mechanism of heterogenous catalysis in your answer.

(1)

Answer

This is a question about water.

(a)

Water might be expected to have a lower boiling temperature than hydrogen sulfide but it actually has a higher boiling temperature.

Comment on this statement by referring to the intermolecular forces in both these substances.

A detailed description of how the intermolecular forces arise is not required.

(4)

Answer

(b)

Explain why both water and carbon dioxide molecules have polar bonds but only water is a polar molecule.

(4)

Answer

(c)

Pure water ionises to form H₃O⁺ and OH^– ions, although only to a very small extent. Draw the dot-and-cross diagrams of these ions. Use dots (•) for the hydrogen electrons and crosses (×) for the oxygen electrons.

(2)

Answer

(d)

An equation for the ionisation of water is

$Question 6, shown as an image$

The expression for the ionic product of water is

$Question 6, shown as an image$

The value of K_w at 310 K is 2.40 × 10^–14 mol² dm^–6

(d)(i)

Calculate the pH of water at 310 K.

Give your answer to two decimal places.

(2)

Answer

(d)(ii)

Predict, with a reason, whether water is acidic, alkaline or neutral at 310 K.

(2)

Answer

(d)(iii)

Predict, with a reason, the sign of the enthalpy change for the ionisation of water.

(1)

Answer

* 7 Colour is often used in chemistry to identify substances.

Compare and contrast the origin of the colour of a copper(II) complex with the origin of the colour of the copper(II) ion in a flame test.

You do not need to state any specific colours.

(6)

Answer

Sodium hydride, NaH, can be used to generate hydrogen for fuel cells.

(a)

(a)(i)

Identify and correct the two errors in this Born-Haber cycle.

(2)

Answer

(a)(ii)

Calculate the first electron affinity, in kJ mol^–1, of hydrogen, using the values given in the cycle.

(1)

Answer

(b)

(b)(i)

(2)

Answer

(b)(ii)

(1)

Answer

(c)

The sodium hydride is crushed in the presence of water to release the hydrogen gas for a fuel cell.

The overall equation for the reaction occurring in the fuel cell is

$Question 8, shown as an image$

In an alkaline fuel cell the oxidation half-equation is

$Question 8, shown as an image$

Deduce the reduction half-equation for the alkaline fuel cell.

State symbols are not required.

(1)

Answer

(d)

Lattice energies provide an indication of ionic bond strength.

Which are the lattice energies of the hydrides NaH, KH and MgH₂?

(1)

Answer

This is a question about buffer solutions.

(a)

A buffer solution always

$Question 9, shown as an image$

(1)

Answer

(b)

A buffer solution with a pH of 3.90 is required. Calculate the mass, in grams, of sodium ethanoate that should be added to 50.0 cm³ of an ethanoic acid solution of concentration 0.800 mol dm^–3 to form this buffer solution.

Give your answer to an appropriate number of significant figures.

[K_a for ethanoic acid = 1.74 × 10^–5 mol dm^–3]

(5)

Answer

(c)

One of the systems controlling the pH of blood is the carbonic acid-hydrogencarbonate buffer system.

$Question 9, shown as an image$

Explain how this buffer system helps to control the pH of blood when extra carbon dioxide is present due to strenuous exercise.

(3)

Answer

(d)

A weak acid-strong base titration curve can be used to demonstrate buffer action.

(d)(i)

Draw a titration curve for the addition of 100 cm³ of sodium hydroxide solution of concentration 0.100 mol dm^–3 to 40.0 cm³ of propanoic acid solution of concentration 0.100 mol dm^–3 which has a pH of 3.0.

Show the part of the curve that demonstrates buffer action.