Calculate the no. of moles in 128g of O2? Share with your friends Share 0 Miss Shinchan answered this molar mass of O2 =32g given mass=128g No. of moles = given mass/molar mass =128/32=4 moles 9 View Full Answer Himanshu Raj answered this Molar mass=32 g Given mass=128g no. of moles=128/32 = 4 moles. 5 Prajwal Raut answered this nic sakshi 0