Physical Chemistry & Transition Elements Random Retrieval

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?

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?

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?

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

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

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.

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!

Consider the following equilibrium for the Haber-Bosch process:

3H_2(g) + N_2(g) <=>2NH_3(g)

32.0 mol of H₂ was combined with 12.0 mol of N₂ and the mixture sealed and pressurised in a vessel of volume 2.00 dm³. The mixture was left until no further observable change in composition took place. At this point, 4.00 mol of NH₃ was found to be present in the mixture The pressure was recorded as 200 000 kPa.

Calculate the value of K_p (in units: kPa^-2) under these conditions.

Consider the values of the equilibrium constant for this reversible reaction:

H_2(g) +I_2(g) <=> 2HI_(g)

Temperature: 500K, value of K_c = 160

Temperature: 1000K, value of K_c = 54.

This information shows that:

(i) HI decomposes rapidly at 500 K

(ii) Raising the temperature causes the equilibrium to shift to the left

(iii) Raising the pressure causes the equilibrium to shift to the right

(iv) The reaction is exothermic

When a sample of calcium carbonate reacts with dilute hydrochloric acid, 144 cm³ of carbon dioxide form in 20 seconds at room temperature and pressure.

What is the rate of loss of hydrochloric acid in moles per second. (Volume of 1 mol gas under these conditions = 24 000 cm³)