Question

(b) Calculate the relative molecular masses of:-

(i)CHCI3 (ii) CuSOa. 5H2O (iii) CH3COO Na

(C= 12, Fl = 1", Cl = 35.5, Cu = 63.5, S = 32, O = 16, Na = 23)​

Answer 1

Answer:

(i) CHCl3

molecular mass = (C) + (H) + 3×(Cl?

molecular mass = (12) + (1) + 3×(35.5) = 119.5

(ii) CuSO4.5H2O

molecular mass = (Cu) + (S) + 4×(O) + 5×{ 2×(H) + (O) }

molecular mass = 63.5 + 32 + 4(16) + 5{ 2(1) + 16 }

molecular mass = 95.5 + 64 + 5(2+16)

molecular mass = 249.5

(iii) CH3COONa

molecular mass = (C) + 3×(H) + (C) + 2×(O) + (Na)

molecular mass = (12) + 3(1) + 12 + 2×(16) + 23

molecular mass = 82