Number of oxygen in one molecule of Na2SO4⋅l0H2O=4+10=14 Thus, moles of oxygen in ' n ' mole of compound is 14n Molar mass of Na2SO4⋅10H2O=46+32+64+180 =322g∕mol Thus, ‌
‌ weight of compound ‌
‌ molar mass of compound ‌
=‌
32.2
322
=0.1mol Now, moles of oxygen =0.1×14=1.4 So, weight =moles× molar mass =16×1.4=22.4g