Category: Chemistry

What temperature is required for the determination of a standard cell potential, E^ϴcell/V?

[1] 298K

[2] 20^oC

[3] 273K

[4] 298 ^oC

What is the value of E^ϴcell/V observed for a cell constructed from the following half-cells?

Zn²⁺_(aq) + 2e^- <=> Zn_(s) E^ϴcell/V = -0.76

Cu²⁺_(aq) + 2e^- <=> Cu_(s) E^ϴcell/V = +0.34

Consider a cell constructed from the following half-cells:

Zn²⁺_(aq) + 2e^- <=> Zn_(s) E^ϴ/V = -0.76

Cu²⁺_(aq) + 2e^- <=>Cu_(s) E^ϴ/V = +0.34

If the solution of Cu²⁺_(aq) was 0.50 mol dm^-3, would you expect to see a greater or smaller value of E^ϴcell/V than you would if the cell was set-up under standard conditions?

Consider a cell constructed from the following half-cells:

Zn²⁺_(aq) + 2e^- <=> Zn_(s) E^ϴ/V = -0.76

Cu²⁺_(aq) + 2e^- <=>Cu_(s) E^ϴ/V = +0.34

Which half-cell will form the cathode in this cell? Think very carefully about the definition of a cathode!

For this question, look at the resource, ‘A Selection of Standard Electrode Potentials’ (‘A Selection of Standard Electrode Potentials’can be found in TOOLS>Data Sheets)

Which chemical species is reduced most easily?

For this question, look at the resource, ‘A Selection of Standard Electrode Potentials’ (‘A Selection of Standard Electrode Potentials’can be found in TOOLS>Data Sheets)

Which chemical species is most resistant to reduction?

For this question, look at the resource, ‘A Selection of Standard Electrode Potentials’ (‘A Selection of Standard Electrode Potentials’can be found in TOOLS>Data Sheets)

Which chemical species is most resistant to oxidation?

For this question, look at the resource, ‘A Selection of Standard Electrode Potentials’ (‘A Selection of Standard Electrode Potentials’can be found in TOOLS>Data Sheets)?

Can MnO₄^-_(aq) oxidise water into H₂O_2(aq) in acidic condition?

Consider a cell constructed from the following half-cells:

Cu²⁺_(aq) + 2e^- <=> Cu_(s) E^ϴ/V = +0.34

Ag⁺_(aq) + e^- <=> Ag_(s) E^ϴ/V = +0.80

Which half-cell forms the anode in this cell? Be very careful with your definition of cathode!

Consider the following 3 equilibria, all involving metallic copper or its ions:

Cu²⁺_(aq) + e^- <=> Cu⁺_(aq) E^ϴ/V = +0.15

Cu²⁺_(aq) + 2e^- <=> Cu_(s) E^ϴ/V = +0.34

Cu⁺_(aq) + e^- <=> Cu_(s) E^ϴ/V = +0.52

An aqueous solution of the colourless compound, CuCl_(s) was prepared and the solution was left to stand for a period in a sealed colourless glass bottle.

After the solution was left to stand, the contents of the bottle would have the following appearance:

When gases are involved in half-cells, what pressure of gas is required for the determination of a standard cell potential, E^ϴcell/V?

What is the value of E^ϴcell/V observed for a cell constructed from the following half-cells?

Fe³⁺_(aq) + e^- <=> Fe²⁺_(aq) E^ϴ/V = +0.77

MnO₄^-_(aq) + 8H⁺_(aq) + 5e^- <=> Mn²⁺_(aq) + 4H₂O_(aq) E^ϴ/V = +1.51

Consider a cell constructed from the following half-cells:

Fe³⁺_(aq) + e^- <=> Fe²⁺_(aq) E^ϴ/V = +0.77

MnO₄^-_(aq) + 8H⁺_(aq) + 5e^- <=> Mn²⁺_(aq) + 4H₂O_(aq) E^ϴ/V = +1.51

If the solution of Fe²⁺_(aq) was 2.00 mol dm^-3, would you expect to see a greater or smaller value of E^ϴcell/V than you would if the cell was set-up under standard conditions?

What is the value of E^ϴcell/V observed for a cell constructed from the following half-cells? These half-cells are those involved in Hydrogen Fuel Cells when operated in acidic conditions?

H⁺_(aq) + e^-<=> ½H_2(g) (acidic conditions) E^ϴ/V = 0.00

O_2(g)+ 4H⁺_(aq) + 4e^-<=>2H₂O_(g) (acidic conditions) E^ϴ/V = +1.23

What is the value of E^ϴcell/V observed for a cell constructed from the following half-cells. (These are the half-cells that are put together in a car battery (6 cells in series)?

PbSO_4(s) + 2e^- <=> Pb_(s) + SO₄^2-_(aq) E^ϴ/V = -0.36

PbO_2(s) + SO₄^2-_(aq)+4H_(aq) + 2e^- <=> PbSO_4(s) + 2H₂O(l) E^ϴ/V = +1.69

High resistance voltmeters are required for accurate values of E^ϴcell/V to be measured.

What statement best describes the reasoning behind the use of a high resistance voltmeter?

For this question, look at the resource, ‘A Selection of Standard Electrode Potentials’ (‘A Selection of Standard Electrode Potentials’can be found in TOOLS>Data Sheets)

Which chemical species is the most powerful oxidising agent?

For this question, look at the resource, ‘A Selection of Standard Electrode Potentials’ (‘A Selection of Standard Electrode Potentials’can be found in TOOLS>Data Sheets)

Under standard conditions, can Mg²⁺_(aq) be reduced to Mg_(s) by Ca_(s)?

For this question, look at the resource, ‘A Selection of Standard Electrode Potentials’ (‘A Selection of Standard Electrode Potentials’can be found in TOOLS>Data Sheets)

Under standard conditions, can Br_2(aq) oxidise Cr³⁺_(aq) to dichromate(VI)?

For this question, look at the resource, ‘A Selection of Standard Electrode Potentials’ (‘A Selection of Standard Electrode Potentials’can be found in TOOLS>Data Sheets)

When nitric(V)acid is added to a purple solution of V²⁺_(aq) ions and the mixture allowed to stand for a few minutes, what colour will be observed in the solution?

What solution concentrations are required for the determination of a standard cell potential, E^ϴcell/V?

What is the value of E^ϴcell/V observed for a cell constructed from the following half-cells?

Mg²⁺_(aq) + 2e^- <=> Mg_(s) E^ϴcell/V = -2.37

Ag⁺_(aq) + e^- <=> Ag_(s) E^ϴcell/V = +0.80

Consider a cell constructed from the following half-cells:

Mg²⁺_(aq) + 2e^- <=> Mg_(s) E^ϴcell/V = -2.37

Ag⁺_(aq) + e^- <=> Ag_(s) E^ϴcell/V = +0.80

If the solution of Mg²⁺_(aq) was 2.00 mol dm^-3, would you expect to see a greater or smaller value of E^ϴcell/V than you would if the cell was set-up under standard conditions?

Thinking carefully about the definitions of anode and cathode in electrochemical cells, an anode is defined as (CARE!):

What is the value of Eϴcell/V observed for a cell constructed from the following half-cells. These half-cells are those involved in Hydrogen Fuel Cells when set-up in alkaline conditions?

2H2O(l) + 2e- <=> 2OH-(aq)+ H2(g) (alkaline conditions) Eϴcell/V = -0.83

O2(g) + 2H2O(l) + 2e- <=> 4OH-(aq) (alkaline conditions) Eϴcell/V = +0.40

For this question, look at the resource, ‘A Selection of Standard Electrode Potentials’ (For this quiz, you will need to open or download the Data Sheet, ‘A Selection of Standard Electrode Potentials’. This can be found in TOOLS>Data Sheets)

Which chemical species is the most powerful reducing agent?

For this question, look at the resource, ‘A Selection of Standard Electrode Potentials’ (‘A Selection of Standard Electrode Potentials’can be found in TOOLS>Data Sheets)

Is Cu²⁺_(aq) capable of oxidising Ag_(s)?

For this question, look at the resource, ‘A Selection of Standard Electrode Potentials’ (‘A Selection of Standard Electrode Potentials’can be found in TOOLS>Data Sheets)

When pieces of tin (Sn) are added a yellow solution of acidified ammonium vanadate(V) containing the VO₂⁺_(aq) ion and the mixture allowed to stand for a few minutes, what colour will be observed in the solution?

Salt bridges are required for a cell E^ϴcell/V to be measured.

What statement best describes the action of a salt bridge?

What is the value of E^ϴcell/V observed for a cell constructed from the following half-cells?

V³⁺_(aq) + e^- <=> V²⁺_(aq) E^ϴcell/V = -0.26

VO₂⁺_(aq) + 2H⁺_(aq) + e^- <=> VO²⁺_(aq) + H₂O_(l) E^ϴcell/V = +1.00

Using your half-equations from questions 10 & 11, balance the REDOX equation below.

S₂O₃^2- + I₂ => S₄O₆^2- + I^-

Select the integers that represent the ratio of species in the overall balanced REDOX equation.

If this question appears in a Random Retrieval quiz, you would be best constructing separate half-equations for the species that is oxidised and the species that is reduced prior to working out the overall REDOX equation.

Work out the ratio of the species in the following half-equation.

I₂ + e^- => I^-

I₂ = [1] 1 [2] 2 [3] 3 [4] 4 [5] 5 [6] 6

e^- = [7] 1 [8] 2 [9] 3 [10] 4 [11] 5 [12] 6

I^- = [13] 1 [14] 2 [15] 3 [16] 4 [17] 5 [18] 6

Work out the ratio of the species in the following half-equation.

S₂O₃^2- => S₄O₆^2- + e^-

Using your half-equations from questions 7 & 8, balance the REDOX equation below.

NO₃^- + H⁺ + Cu => Cu²⁺ + NO₂ + H₂O

Select the integers that represent the ratio of species in the overall balanced REDOX equation.

If this question appears in a Random Retrieval quiz, you would be best constructing separate half-equations for the species that is oxidised and the species that is reduced prior to working out the overall REDOX equation.

Work out the ratio of the species in the following half-equation.

Cu => Cu²⁺ + e^-

Work out the ratio of the species in the following half-equation.

NO₃^- + H⁺ + e^- => NO₂ + H₂O

Using your half-equations from questions 4 & 5, balance the REDOX equation below.

BrO₃^- + H⁺ + C₂O₄^2- => CO₂ + Br^- + H₂O

Select the integers that represent the ratio of species in the overall balanced REDOX equation.

If this question appears in a Random Retrieval quiz, you would be best constructing separate half-equations for the species that is oxidised and the species that is reduced prior to working out the overall REDOX equation.

Work out the ratio of the species in the following half-equation.

C₂O₄^2- => CO₂ + e^-

Work out the ratio of the species in the following half-equation.

BrO₃^- + H⁺ + e^- => Br^- + H₂O

Using your half-equations from questions 1 & 2, balance the REDOX equation below.

O₂ + H⁺ + Br^- => Br₂ + H₂O

Select the integers that represent the ratio of species in the overall balanced REDOX equation.

If this question appears in a Random Retrieval quiz, you would be best constructing separate half-equations for the species that is oxidised and the species that is reduced prior to working out the overall REDOX equation.

Work out the ratio of the species in the following half-equation.

O₂ + e^- + H⁺ => H₂O

Work out the ratio of the species in the following half-equation.

Br^- => Br₂ + e^-

Using oxidation numbers (states) work out the ratio of the species in the following half-equation.

I₂ + e^- => I^-

Using oxidation numbers (states) work out the ratio of the species in the following half-equation.

H₂O => O₂ + H⁺ + e^-

Using oxidation numbers (states) work out the ratio of the species in the following half-equation.

ClO^- + H⁺ + e^- => Cl^- + H₂O

Using oxidation numbers (states) work out the ratio of the species in the following half-equation.

H₂S => S + H⁺ + e^-

Using oxidation numbers (states) work out the ratio of the species in the following half-equation.

H₂SO₄ + H⁺ + e^- => SO₂ + H₂O

Using oxidation numbers (states) work out the ratio of the species in the following half-equation.

MnO₄^- + H ⁺ + e^- => Mn²⁺ + H₂O

Using oxidation numbers (states) work out the ratio of the species in the following half-equation.

Cr₂O₇^2- + H⁺ + e^- => Cr³⁺

+H₂O

Using oxidation numbers (states) work out the ratio of the species in the following half-equation.

S₂O₃^2- + H₂O => SO₄^2- + H⁺ + e^-

Using oxidation numbers (states) work out the ratio of the species in the following half-equation.

S₂O₃^2- => S₄O₆^2- + e^-

Using oxidation numbers (states) work out the ratio of the species in the following half-equation.

H₂O₂ + H⁺ + e^- => H₂O

Which types of chemical bonding feature in crystals of the compound K₂[Ni(CN)₄]?

(i) ionic bonding

(ii) covalent bonding

(iii) dative covalent bonding

(iv) metallic bonding

Which of these complex ions acts as an acid in aqueous solution?

(i) [Ni(NH₃)₆]²⁺

(ii) [Al(H₂O)₂(OH)₄]^-

(iii) [Ag(NH₃)₂]⁺

(iv) [Cr(H₂O)₆]3⁺

Which of the following can act as a bidentate ligand in the formation of complexes with metal ions?

(i) S₂O₃^2-

(ii) C₂O₄^2-

(iii) SCN^-

(iv) H₂NCH₂CH₂NH₂

When four bromide ions combine with a cobalt(II) ion

(i) the charge on the complex ion is 2-

(ii) the shape of the complex ion is tetrahedral

(iii) the coordination number of the cobalt atom is 4

(iv) the name of the complex is the tetrabromocobalt (II) ion

The compound with the formula K₃[Fe(CN)₆]

(i) is potassium hexacyanoferrate(III)

(ii) contains a complex with an octahedral shape

(iii) includes iron in the oxidation state +3

(iv) contains an hexadentate ligand

Which of these complex ions have a colour in solution?

(i) [Sc(H₂O)₃]²⁺

(ii) [CuCl₂]^-

(iii) [Zn(OH)₄]^2-

(iv) [Co(H₂O)₆]²⁺

In which of these complexes is the oxidation state of the metal +3?

(i) [Fe(H₂O)₅SCN]²⁺

(ii) [CoCl₄]^2-

(iii) [Cr(H₂O)₄Cl₂]⁺

(iv) [Ag(S₂O₃)₂]^2-

Which of the statements below are true of this reaction?

[Cu(H₂O)₆]²⁺(aq) + 4NH₃(aq) <=> [Cu(NH₃)₄(H₂O)₂]²⁺(aq) + 4H₂O(aq)

(i) Copper disproportionates,

(ii) It is a proton transfer reaction,

(iii) Ammonia is oxidised,

(iv) It is a ligand exchange reaction

In an EDTA complex with a copper(II) ion

(i) there are six ligand molecules,

(ii) there are four dative bonds between oxygen atoms and the metal ion,

(iii) the overall charge on the complex ion is zero,

(iv) there are two dative bonds between nitrogen atoms and the metal ion

In the anti-cancer complex compound [Pt(NH₃)₂Cl₂]

(i) the Pt, N and Cl atoms lie in one plane

(ii) the N-Pt-N angle is 180^o

(iii) the Cl-Pt-Cl angle is 90^o

(iv) the coordination number of platinum is zero

Which first-row d-block element has the electron configuration

1s²2s²2p⁶3s²3p⁶4s¹3d⁵?

Which of the first-row d-block metals forms aqueous ions which are mauve in the +2 state, green in the +3 state, blue in the +4 state and yellow in the +5 state?

Which first-row d-block metal forms aqueous ions in the +6 state which are orange in acid solution but yellow in alkaline solution?

Which first-row d-block metal has the main oxidation state +2 and forms colourless compounds?

Which first-row d-block metal forms aqueous ions in the +3 state which oxidise iodide ions to iodine?

Which first-row d-block metal forms a reddish oxide in the +1 state which dissolves in dilute sulfuric acid to give a blue solution and a red-brown precipitate?

Which metal forms aqueous ions in the +2 state which precipitate as a hydroxide on adding ammonia solution and redissolve to form a deep blue solution

Which first-row d-block metal forms hydrated ions in the +3 state which undergo a ligand exchange reaction to form a deep red complex ion with thiocyanate ions, SCN^-.

Which first-row d-block element forms an oxide used as the catalyst in the synthesis of sulfur trioxide from sulfur dioxide and oxygen?

Which first-row d-block element is used as the catalyst for the addition of hydrogen gas to C=C double bonds?

Look at the chemical equation below.

2NaHCO_3(s)=> Na₂CO_3(s)+ H₂O_(g)+ CO_2(g)

By selecting the appropriate data from the ‘Selection of Thermodynamic Data’ in TOOLS, calculate the entropy change, ΔS^Ɵ for the process. Take care with states!

Look at the chemical equation below.

2NaHCO_3(s)=> Na₂CO_3(s)+ H₂O_(g)+ CO_2(g)

By selecting the appropriate data from the ‘Selection of Thermodynamic Data’ in TOOLS, calculate the enthalpy change ΔH^Ɵ for the process. Take care with states!

Look at the chemical equation below.

2NaHCO_3(s)=> Na₂CO_3(s)+ H₂O_(g)+ CO_2(g)

Using your answers to Questions 1 and 2, calculate the Gibbs Energy change, ΔG, for the process if it is carried out in an oven at 100^oC.

If this question is from a Random Retrieval, you can also carry out this calculation by first working out values for ΔS^Ɵ and ΔH^Ɵ by selecting the appropriate data from the ‘Selection of Thermodynamic Data’ in TOOLS.

From your calculation of ΔG in question 3, decide whether a solid dry sample of NaHCO_3(s) will decompose or will be thermally stable in the oven at 100^oC.

If this question is from a Random Retrieval, you can also carry out this calculation of Gibbs Energy change, ΔG, by first working out values for ΔS^Ɵ and ΔH^Ɵ by selecting the appropriate data from the ‘Selection of Thermodynamic Data’ in TOOLS.

Look at the chemical equation below.

2NaHCO_3(s)=> Na₂CO_3(s)+ H₂O_(g)+ CO_2(g)

Calculate the temperature at which this process becomes feasible.

If this question is from a Random Retrieval, you can also carry out this calculation by first working out values for ΔS^Ɵ and ΔH^Ɵ by selecting the appropriate data from the ‘Selection of Thermodynamic Data’ in TOOLS.

Look at the chemical equation below.

CH_4(g) + H₂O_(g)=> CO_(g)+ 3H_2(g)

By selecting the appropriate data from the ‘Selection of Thermodynamic Data’ in TOOLS, calculate the entropy change, ΔS^Ɵ for the process. Take care with states!

Look at the chemical equation below.

CH_4(g) + H₂O_(g)=> CO_(g)+ 3H_2(g)

By selecting the appropriate data from the ‘Selection of Thermodynamic Data’ in TOOLS, calculate the enthalpy change ΔH^Ɵ for the process. Take care with states!

Look at the chemical equation below.

CH_4(g) + H₂O_(g)=> CO_(g)+ 3H_2(g)

Using your answers to Questions 6 and 7, calculate the Gibbs Energy change ΔG, for the process if it is carried out in a reactor vessel at 1500^oC.

If this question is from a Random Retrieval, you can also carry out this calculation by first working out values for ΔS^Ɵ and ΔH^Ɵ by selecting the appropriate data from the ‘Selection of Thermodynamic Data’ in TOOLS.

From your calculation of ΔG in question 8, decide whether the reaction between high pressure steam and methane will be feasible at 1500^oC.

If this question is from a Random Retrieval, you can also carry out this calculation of Gibbs Energy change, ΔG by first working out values for ΔS^Ɵ and ΔH^Ɵ by selecting the appropriate data from the ‘Selection of Thermodynamic Data’ in TOOLS.

Look at the chemical equation below.

CH_4(g) + H₂O_(g)=> CO_(g)+ 3H_2(g)

Calculate the temperature at which this process just becomes feasible.

If this question is from a Random Retrieval, you can also carry out this calculation by first working out values for ΔS^Ɵ and ΔH^Ɵ by selecting the appropriate data from the ‘Selection of Thermodynamic Data’ in TOOLS.

What enthalpy change is represented by the following equation?

Ca_(s) => Ca_(g)

What enthalpy change is represented by the following equation?

S^-_(g) + e^-=> S^2-_(g)

What enthalpy change is represented by the following equation?

Al²⁺_(g) => Al³⁺_(g) + e^-

What enthalpy change is represented by the following equation?

2Na_(s) + ½ O_2(g)=> Na₂O_(s)

What enthalpy change is represented by the following equation?

½ Br_2(l) => Br_(g)

What enthalpy change is represented by the following equation?

Mg²⁺_(g) + 2F^-_(g) => MgF_2 (s)

What enthalpy change is represented by the following equation?

Cl_(g) + e^-=> Cl^-_(g)

Calculate the value of the enthalpy change associated with the following equation?

2Cl_2(g)=> 4Cl_(g)

Calculate the value of the enthalpy change associated with the following equation?

N_2(g) + 3H_2(g) => 2NH_3(g)

Calculate the value of the enthalpy change associated with the following equation?

3Rb_(g)=> 3Rb_(s)

For which of these changes is the enthalpy change the standard enthalpy of atomisation of bromine?

The energy change for this process:

Br_(g) + e^- -> Br^-_(g)is called the:

The standard enthalpy change when one mole of an ionic compound forms from free gaseous ions is called the:

These are four values for the hydration enthalpies of ions:

-361 kJ mol^-1, -559 kJ mol^-1, -2003 kJ mol^-1, -2537 kJ mol^-1.

These ions from left to right are:

What is the enthalpy of solution of lithium bromide given that:

the lattice enthalpy for LiBr = -818 kJ mol^-1

enthalpy of hydration of Li⁺ ions = -559 kJ mol^-1

enthalpy of hydration of Br^- ions = -309 kJ mol^-1

The lattice enthalpy for magnesium oxide is -3850 kJ mol^-1.

The energy needed to break up 0.1 mol MgO into gaseous ions at 298K is:

[1] -38.5 kJ mol-1

[2] -385 kJ mol^-1

[3] +385 kJ mol^-1

[4] +3850 kJ mol^-1

For which of these compounds would expect the best agreement between the values of the lattice energy derived from experimental data (with the help of the Born-Haber cycle) and the values calculated from theory on the assumption that the bonding in the crystals is purely ionic?

The extent to which the negative ions are polarised by neighbouring positive ions in these crystals increase from left to right in which of these series?

(i) KF - KCl - KBr

(ii) LiI - NaI - KI

(iii) NaBr - MgBr₂ - AlBr₃

(iv) MgF₂ - CaF₂ - SrF₂

The magnitude (numerical value) of the lattice enthalpy for these compounds increase from left to right putting first the compound with the least negative value?

(i) LiCl - LiBr - LiI

(ii) MgO - BaO - BaS

(iii) NaCl - KCl - RbCl

(iv) NaF - MgF₂ - AlF₃