Lead can be prepared from galena [lead(ii) sulfide] by first roasting the galena in oxygen gas to form lead(ii) oxide and sulfur dioxide. Heating the metal oxide with more galena forms the molten metal and more sulfur dioxide. Required:
a. Write a balanced equation for each step.
b. Write an overall balanced equation for the process.
c. How many metric tons of sulfur dioxide form for every metric ton of lead obtained?