Identification of ions

This question is about inorganic chemistry.

The flowchart shows reactions involving SO₃^2–(aq) ions.

What is the systematic name of a SO₃^2– ion?

Construct an ionic equation for the reaction of SO₃^2– with H⁺/Cr₂O₇^2–.

The structure of a neutral nickel(II) complex, A, is shown below.

What is the empirical formula of complex A ?

Complete the 3D diagram below to show a stereoisomer of complex A.

A student analyses a solution of a salt.

The results are shown below.

What is the formula of the salt?

A CuCl₂

B CuSO₄

C FeCl₂

D FeSO₄

Your answer

This question is about different areas of chemistry.

Why do all average bond enthalpies have a positive value?

Determine the C–H bond enthalpy, in kJ mol^–1, using the information above.

C–H bond enthalpy =........ kJ mol^–1

Hydrogen gas is being considered as a household fuel to replace methane.

The enthalpy change of formation, _fH, for H₂O(l) is –285.8 kJ mol^–1.

Determine the energy released when 60.0 m³ of hydrogen is used as a household fuel at RTP.

Give your answer to 3 significant figures and in standard form.

Compound A is a chloride of a Period 3 element.

A student carries out the 2 steps below to find the formula of compound A.

Step 1 The student adds 5.00 10^–4 mol of compound A to water. A colourless solution is formed.

Step 2 The colourless solution reacts with exactly 60.0 cm³ of 2.50 10^–2 mol dm^–3 AgNO₃(aq) to form a white precipitate.

Write an ionic equation, with state symbols, for the reaction in Step 2.

Determine the formula of compound A.

Compound B, shown below, is an antiviral medicine.

What is the molecular formula of compound B ?

How many chiral carbon atoms are there in one molecule of compound B ?

A student adds aqueous potassium carbonate to one test tube and aqueous silver nitrate to a second test tube.

The student adds dilute hydrochloric acid to each test tube.

Which row has the correct observations?

Your answer

Tutton’s salts are ‘double salts’ with the formula X₂Y(ZO₄)₂ • 6H₂O.

A Tutton’s salt contains two cations: X⁺ and Y²⁺.

• X + can be an ion of the Group 1 elements K, Rb, Cs or Fr, or an ammonium ion.

• Y²⁺ can be a 2+ ion of magnesium or an ion of most of the transition elements in Period 4.

• Z can be S or Cr.

(NH₄)₂Cu(SO₄)₂ • 6H₂O is an example of a Tutton’s salt.

Predict the formula of a Tutton’s salt containing different ions from (NH₄)₂Cu(SO₄)₂ • 6H₂O.

A student prepares a sample of the Tutton’s salt, (NH₄)₂Cu(SO₄)₂ • 6H₂O using the method shown below.

Step 1 Dissolve 0.025 mol of ammonium sulfate and 0.025 mol of hydrated copper(II) sulfate, CuSO₄ • 5H₂O, in water and make up to 50 cm³.

Step 2 Boil the resulting mixture for 2 minutes and allow to cool.

Step 3 Allow the solvent to evaporate slowly. Pale blue crystals of the Tutton’s salt form.

What masses are needed of ammonium sulfate and CuSO₄ • 5H₂O?

mass of ammonium sulfate........ g

mass of CuSO₄ • 5H₂O........ g

In Step 3, why does the student allow the solvent to evaporate and not boil off all the solvent in Step 2 ?

The student dissolves their Tutton’s salt in water. A pale blue solution forms.

The student carries out two tests on this aqueous solution.

The student adds an excess of aqueous ammonia to their aqueous solution of Tutton’s salt. A deep blue solution forms.

The complex ion responsible for the deep blue solution has a molar mass of 167.5 g mol^–1.

Suggest the formula of this complex ion.

The student adds NaOH(aq) to the aqueous solution of Tutton’s salt and warms the mixture.

A precipitate and a gas are formed.

Write the formulae of the precipitate and gas and suggest a test that could confirm the identity of the gas.

Formula of precipitate........

Formula of gas........

Test to confirm the identity of the gas........

How could the student carry out a test-tube test to confirm the anion in the Tutton’s salt?

An aqueous solution contains a mixture of chloride, bromide and iodide ions.

AgNO₃(aq) is added to this mixture, followed by an excess of dilute NH₃(aq).

The resulting mixture is then filtered.

Which compound(s) is/are present in the residue on the filter paper?

A AgC l only

B AgC l and AgBr

C AgBr only

D AgBr and Ag I

Your answer

Two students plan to investigate Equilibrium 4.1, shown below.

The students are supplied with the equilibrium mixture in Equilibrium 4.1 at room temperature.

• One student heats 20 cm³ of the mixture to 50 °C.

• The other student heats 20 cm³ of the mixture to 90 °C.

The students use colorimetry to observe how the colour of the equilibrium mixture changes over time.

• The colorimeter is set up so that the greater the absorbance, the greater the

The students plot the graph below from the results of the experiment.

Use the graph and relevant chemical theory to answer the following. Include all reasoning:

• Explain the different initial rates at 50 °C and 90 °C.

• Predict the sign of ∆ H for the forward reaction in Equilibrium 4.1.

The students investigate how addition of aqueous silver nitrate, AgNO₃(aq), affects the equilibrium position in Equilibrium 4.1.

The graph shows the changes in the equilibrium concentrations of CoCl₄^2–, Cl^– and [Co(H₂O)₆]²⁺ after addition of the AgNO₃(aq).

The AgNO₃(aq) is added at time = t₁.

Explain why the Cl^– concentration drops sharply at time = t₁.

NH₄Fe(SO₄)₂•12H₂O is a hydrated ‘double salt’.

A student analyses this double salt using test tube tests.

Which row(s) gives/give correct result(s) for the stated test?

A 1, 2 and 3

B Only 1 and 2

C Only 2 and 3

D Only 1

Your answer

Which statement about ammonium carbonate is not correct?

A It reacts with Ba(NO₃)₂(aq) to form a white precipitate.

B It effervesces with dilute nitric acid.

C It release an alkaline gas with warm NaOH(aq).

D It has the formula NH₄CO₃.

Your answer