1. Answer the following questions related to manganese compounds. — Atomic Structure, Empirical Formula, Electrochemistry Chemistry Question
Problem Context
- Answer the following questions related to manganese compounds.
(a) Manganese has several common oxidation states.
(i) Write the complete electron configuration for an Mn atom in the ground state.
(ii) When manganese forms cations, electrons are lost from which subshell first? Identify both the number and letter associated with the subshell.
A student performs an experiment to produce a manganese salt of unknown composition, MnxCly(aq), and determine its empirical formula. The student places a sample of Mn(s) in a beaker containing excess HCl(aq), as represented by the following equation.
x Mn(s) + y HCl(aq) → MnxCly(aq) + y/2 H2(g)
The student heats the resulting mixture until only MnxCly(s) remains in the beaker. The data are given in the following table.
(b) Calculate the mass of Cl in the sample of MnxCly(s) remaining in the beaker.
(c) Calculate the number of moles of Cl in the sample of MnxCly(s) remaining in the beaker.
(d) The student determines that 0.0199 mol of Mn was used in the experiment. Use the data to determine the empirical formula of the MnxCly(s).
(e) The student repeats the experiment using the same amounts of Mn and HCl and notices that some of the MnxCly splatters out of the beaker as it is heated to dryness. Will the number of moles of Cl calculated for this trial be greater than, less than, or equal to the number calculated in part (c) ? Justify your answer.
(f) Another compound of manganese, MnO2, is used in alkaline batteries, represented by the following diagram. Some half-reactions are given in the table.
(i) Based on the half-reactions given in the table, write the balanced net ionic equation for the reaction that has the greatest thermodynamic favorability.
(ii) Calculate the value of E°cell for the overall reaction.
(iii) Calculate the value of ΔG° in kJ/mol rxn .
(iv) A student claims that the total mass of an alkaline battery decreases as the battery operates because the anode loses mass. Do you agree with the student’s claim? Justify your answer.