9.2.REDOX-P2 [93 marks]
1.
[Maximum mark: 8]
Consider the following reaction:
22N.2.sl.TZ0.3
Cu2+ (aq) + Fe (s) → Fe2+ (aq) + Cu (s)
(a)
State the ground-state electron configuration for Fe2+.
(b)
The mass spectrum for copper is shown:
[1]
Source: WebElements, n.d. Copper: isotope data [online] Available at:
https://www.webelements.com/copper/isotopes.html [Accessed 6 October 2021].
Show how a relative atomic mass of copper of 63.62 can be
obtained from this mass spectrum.
The diagram shows an unlabelled voltaic cell for the reaction:
Cu2+ (aq) + Fe (s) → Fe2+ (aq) + Cu (s)
[1]
(c.i)
(c.ii)
(c.iii)
(c.iv)
Label the diagram with the species from the equation and the
direction of electron flow.
[2]
Write the half-equation for the reaction occurring at the anode
(negative electrode).
[1]
The diagram includes a salt bridge that is filled with a saturated
solution of KNO3. Outline the function of the salt bridge.
[1]
Predict the movement of all ionic species through the salt
bridge.
[2]
2.
[Maximum mark: 12]
Magnesium is a reactive metal often found in alloys.
(a)
(b)
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Magnesium can be produced by the electrolysis of molten
magnesium chloride.
Write the half-equation for the formation of magnesium.
[1]
Suggest an experiment that shows that magnesium is more
reactive than zinc, giving the observation that would confirm
this.
[2]
Organomagnesium compounds can react with carbonyl compounds. One
overall equation is:
(c(i))
State the name of Compound A, applying International Union
of Pure and Applied Chemistry (IUPAC) rules.
(c(ii)) Identify the strongest force between the molecules of
Compound B.
Compound B can also be prepared by reacting an alkene with water.
(d(i)) Draw the structural formula of the alkene required.
[1]
[1]
[1]
(d(ii)) Deduce the structural formula of the repeating unit of the
polymer formed from this alkene.
(e)
Deduce what would be observed when Compound B is
warmed with acidified aqueous potassium dichromate (VI).
[1]
[1]
Iodomethane is used to prepare CH3MgI. It can also be converted into methanol:
CH3I + HO– → CH3OH + I–
(f(i))
Identify the type of reaction.
(f(ii)) Outline the requirements for a collision between reactants to
yield products.
[1]
[2]
(f(iii)) The polarity of the carbon–halogen bond, C–X, facilitates attack
by HO–.
Outline, giving a reason, how the bond polarity changes going
down group 17.
[1]
3.
[Maximum mark: 4]
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Molten zinc chloride undergoes electrolysis in an electrolytic cell at 450 °C.
(a)
Deduce the half-equations for the reaction at each electrode.
[2]
(b)
Deduce the overall cell reaction including state symbols. Use
section 7 of the data booklet.
[2]
4.
[Maximum mark: 4]
21M.2.sl.TZ2.3
Oxidation and reduction reactions can have a variety of commercial uses.
(a)
A student decides to build a voltaic cell consisting of an
aluminium electrode, Al (s), a tin electrode, Sn (s), and solutions
of aluminium nitrate, Al(NO3)3 (aq) and tin(II) nitrate, Sn(NO3)2
(aq).
Electron flow is represented on the diagram.
Label each line in the diagram using section 25 of the data
booklet.
[3]
(b)
Write the equation for the expected overall chemical reaction in
(a).
[1]
5.
[Maximum mark: 11]
Nickel catalyses the conversion of propanone to propan-2-ol.
20N.2.sl.TZ0.4
(a)
Outline how a catalyst increases the rate of reaction.
[1]
(b)
Explain why an increase in temperature increases the rate of
reaction.
[2]
Discuss, referring to intermolecular forces present, the relative
volatility of propanone and propan-2-ol.
[3]
(c)
(d(i)) The diagram shows an unlabelled voltaic cell for the reaction
Pb
2+
(aq) + Ni (s) → Ni
2+
(aq) + Pb (s)
Label the diagram with the species in the equation.
[1]
(d(ii)) Suggest a metal that could replace nickel in a new half-cell and
reverse the electron flow. Use section 25 of the data booklet.
[1]
(d(iii)) Describe the bonding in metals.
[2]
(d(iv)) Nickel alloys are used in aircraft gas turbines. Suggest a physical
property altered by the addition of another metal to nickel.
[1]
6.
[Maximum mark: 13]
Copper forms two chlorides, copper(I) chloride and copper(II) chloride.
(a(i))
State the electron configuration of the Cu+ ion.
19N.2.sl.TZ0.5
[1]
(a(ii)) Copper(II) chloride is used as a catalyst in the production of
chlorine from hydrogen chloride.
4HCl (g) + O2 (g) → 2Cl2 (g) + 2H2O (g)
Calculate the standard enthalpy change, ΔHθ, in kJ, for this
reaction, using section 12 of the data booklet.
[2]
(a(iii)) The diagram shows the Maxwell–Boltzmann distribution and
potential energy profile for the reaction without a catalyst.
Annotate both charts to show the activation energy for the
catalysed reaction, using the label Ea (cat).
[2]
(a(iv)) Explain how the catalyst increases the rate of the reaction.
(b)
Solid copper(II) chloride absorbs moisture from the atmosphere
to form a hydrate of formula CuCl2• xH2O.
A student heated a sample of hydrated copper(II) chloride, in
order to determine the value of x. The following results were
obtained:
[2]
Mass of crucible = 16.221 g
Initial mass of crucible and hydrated copper(II) chloride =
18.360 g
Final mass of crucible and anhydrous copper(II) chloride =
17.917 g
[3]
Determine the value of x.
An electrolysis cell was assembled using graphite electrodes and connected as
shown.
(c(i))
State how current is conducted through the wires and through
the electrolyte.
Wires:
Electrolyte:
(c(ii)) Write the half-equation for the formation of gas bubbles at
electrode 1.
[2]
[1]
7.
[Maximum mark: 5]
This question is about iron.
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(a)
State the nuclear symbol notation,
(b)
Mass spectrometry analysis of a sample of iron gave the
following results:
A
Z
, for iron-54.
X
Calculate the relative atomic mass, Ar, of this sample of iron to
two decimal places.
(c)
[1]
[2]
An iron nail and a copper nail are inserted into a lemon.
Explain why a potential is detected when the nails are
connected through a voltmeter.
[2]
8.
[Maximum mark: 5]
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The diagram shows an incomplete voltaic cell with a light bulb in the circuit.
(a)
Identify the missing component of the cell and its function.
(b)
Deduce the half-equations for the reaction at each electrode
when current flows.
[2]
[2]
(c)
Annotate the diagram with the location and direction of
electron movement when current flows.
[1]
9.
[Maximum mark: 9]
The emission spectrum of an element can be used to identify it.
(a.i)
18M.2.sl.TZ2.3
Draw the first four energy levels of a hydrogen atom on the axis,
labelling n = 1, 2, 3 and 4.
[1]
(a.ii)
Draw the lines, on your diagram, that represent the electron
transitions to n = 2 in the emission spectrum.
[1]
Elements show trends in their physical properties across the periodic table.
(b.i)
Outline why atomic radius decreases across period 3, sodium to
chlorine.
[1]
(b.ii)
Outline why the ionic radius of K+ is smaller than that of Cl−.
[2]
(c.i)
Copper is widely used as an electrical conductor.
Draw arrows in the boxes to represent the electronic
configuration of copper in the 4s and 3d orbitals.
[1]
(c.ii)
Impure copper can be purified by electrolysis. In the electrolytic
cell, impure copper is the anode (positive electrode), pure
copper is the cathode (negative electrode) and the electrolyte is
copper(II) sulfate solution.
Formulate the half-equation at each electrode.
[2]
(c.iii)
Outline where and in which direction the electrons flow during
electrolysis.
[1]
10.
[Maximum mark: 11]
Trends in physical and chemical properties are useful to chemists.
(a)
(b)
(c)
(d)
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Explain the general increasing trend in the first ionization
energies of the period 3 elements, Na to Ar.
[2]
Explain why the melting points of the group 1 metals (Li → Cs)
decrease down the group.
[2]
State an equation for the reaction of phosphorus (V) oxide,
P 4O10 (s), with water.
[1]
Describe the emission spectrum of hydrogen.
[2]
The Activity series lists the metal in order of reactivity.
(e.i)
Identify the strongest reducing agent in the given list.
(e.ii)
A voltaic cell is made up of a Mn2+/Mn half-cell and a Ni2+/Ni
half-cell.
Deduce the equation for the cell reaction.
(e.iii) The voltaic cell stated in part (ii) is partially shown below.
Draw and label the connections needed to show the direction
of electron movement and ion flow between the two half-cells.
[1]
[1]
[2]
11.
[Maximum mark: 11]
16N.2.sl.TZ0.4
Magnesium is a group 2 metal which exists as a number of isotopes and forms
many compounds.
(a)
State the nuclear symbol notation,
(b)
Mass spectroscopic analysis of a sample of magnesium gave the
following results:
A
Z
, for magnesium-26.
X
[1]
Calculate the relative atomic mass, Ar, of this sample of
magnesium to two decimal places.
[2]
Magnesium burns in air to form a white compound, magnesium
oxide. Formulate an equation for the reaction of magnesium
oxide with water.
[1]
Describe the trend in acid-base properties of the oxides of
period 3, sodium to chlorine.
[2]
In addition to magnesium oxide, magnesium forms another
compound when burned in air. Suggest the formula of this
compound
[1]
(f )
Describe the structure and bonding in solid magnesium oxide.
[2]
(g)
Magnesium chloride can be electrolysed.
(c)
(d)
(e)
Deduce the half-equations for the reactions at each electrode
when molten magnesium chloride is electrolysed, showing the
state symbols of the products. The melting points of
magnesium and magnesium chloride are 922 K and 987 K
respectively.
Anode (positive electrode):
Cathode (negative electrode):
© International Baccalaureate Organization, 2023
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