question_answer

  Calculate the molar mass of the following compounds. (a) Lead sulphate             (b) Calcium phosphate [Given atomic masses of various elements Ca = 40, S = 32, 0 = 16, Pb = 207, P = 31]

Answer:

  Molar mass of lead sulphate = atomic mass of Pb + atomic mass of S + 4 x atomic mass of O = 207 + 32 + 4 x 16 = 207+32+64 =303 u                 (b) Molar mass of calcium phosphate = 3 x atomic mass of Ca + 2 x (atomic mass of P + 4 x atomic mass of O) = 3 x 40 + 2x (31 + 4x16) = 120 + 2x (31 + 64) =120 + 2x95 = 120 +190 = 310 u