rate of 10mmol/hr means 10 milli moles  in hour
                                     Â
10*10-3 moles in one hour
                                    Â
43*10*10-2 moles in 43 hours
                                   Â
4.3 moles in 43 hours
                                 Â
decreases no of moles = 6.9-4.3 = 2.6 moles of helium after 43
hours
6.9 moles of helium volume is 110L
2.6 moles of helium volume is = 110*2.6/6.9Â Â = 41.449
L
volume of ballon after 43 hours is 41.449L >>>>>
answer
