Question

If a 1.00 L flask containing 1.00 atm of SO2 is connected to a 4.00 L flask containing 1.00 atm of O2, and the gases are allowed to mix and react to form SO3 at 25°C, predict the total pressure (PT) in the flask after the reaction is over

a. 1.10 atm

b.

0.300 atm

c.

0.900 atm

d.

0.200 atm

Answer 1

No of mol of SO2 reacted = PV/RT

                           = (1*1/(0.0821*298.15))

              = 0.04 mol

No of mol of SO2 reacted = PV/RT

                           = (1*4/(0.0821*298.15))

                          = 0.163 mol

2so2 + o2 ---> 2so3

2 mol so2 = 1 mol o2

limiting reactant = so2

No of mol of SO3 produced = 0.04*2/2 = 0.04 mol

No of mol of o2 unreacted = 0.163-(0.04/2) = 0.143 mol

total moles = 0.143+0.04 = 0.183 mol

the total pressure = nRT/V

                  = 0.183*0.0821*298/5

                  = 0.895 atm
answer: c.0.9 atm