Question

Roasting galena [lead(II) sulfide] is an early step in the industrial isolation of lead. How many liters of sulfur dioxide, measured at STP, are produced by the reaction of 7.16 kg of galena with 166 L of oxygen gas at 220 Celsius and 2.00 atm? Lead(II) oxide also forms.

How much of SO_{2 in liters is produced?}

Answer 1

2PbS + 3O2 -------------> 2PbO + 2SO2

PV = nRT

V   = 166L

T   = 220+273 = 493K

P = 2atm

n = PV/RT

     = 2*166/0.0821*493   = 8.2 moles of O2

weight of PbS   = 7.16Kg = 7160g

no of moles of PbS    = W/G.M.Wt

                                    = 7160/239   = 30 moles

2PbS + 3O2 -------------> 2PbO + 2SO2

2 moles of PbS react with 3moles of O2

30 moles of PbS react with = 3*30/2   = 45 moles of O2

O2 is limiting reactant

3 moles of O2 react with PbS to gives 2 moles of SO2

3 moles of O2 react with PbS to gives 2*22.4L of SO2

8.2 moles of O2 react with PbS to gives =2*22.4*8.2/3   = 122.45L of So2