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 most resistant to reduction?

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?

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.

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.

Why does the term [H₂O_(l)]not appear in the expression for K_a for methanoic acid?

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 following reaction:

2H₂O_2(g) => 2H₂O_(g)+ O_2(g)

The rate equation was found, by experiment:

rate = k [H₂O₂]

Which of the following statements is/are true?

(i) The mechanism must be multi step

(ii) Doubling [H₂O_{] quadruples the rate of the reaction}

(iii) [H₂O] must be consumed in more than one step

(iv) The mechanism probably has only one step

Consider the following reaction:

NO_2(g) + CO_(g) => NO_(g)+ CO_2(g)

The rate equation was found, by experiment:

rate = k [NO₂]²

Which of the following statements is/are true?

(i) The mechanism has more than one step

(ii) CO is involved in the rate determining step

(iii) NO₂ is produced in one of the steps

(iv) The mechanism has only one step

What are the units of k for this reaction?

Nitrogen monoxide gas reacts with oxygen gas to form nitrogen dioxide gas. If the rate of formation of nitrogen dioxide is 1.4 x 10^-5 mol dm^-3, what is the rate of disappearance of oxygen?