total pressure = 666/760=0.876 atm
moles gas = 0.876 x 1.10 L / 0.08206 x 298 K=0.0394
moles N2 / 0.0394 = 330/ 666
moles N2 =0.0195
mass N2 = 0.0195 x 28.0134 g/mol= 0.546 g
moles O2 / 0.0394 = 126/666
moles O2 = 0.00745
mass O2 = 0.00745 x 32 g/mol=0.239 g
moles He/ 0.0394 = 210/ 666
moles He = 0.0124
mass He = 0.0124 x 4 g/mol=0.0497 g
