Question

(a) Calculate the molecular mass of: [4] [C =12, O =16, N =14, H =1, Cl =35.5, Na = 23, Fe =56, S = 32,]
(i) Na2CO3 (ii) Cane sugar C12H22O11
(iii)(NH4)2SO4 (iv) Iron [III] chloride

Answer 1

Answer:

(i) Na2CO3 - 106 g/mol

(ii) C12H22O11 - 342 g/mol

(iii) (NH4)2SO4 - 132 g/mol

(iv) FeCl3 - 162.5 g/mol

Explanation:

(i) Na2CO3 -

[(2 x 23) + (1 x 12) + (3 x 16)]

= 46 + 12 + 48

= 106 g/mol

(ii) C12H22O11 -

[(12 x 12) + (22 x 1) + (11 x 16)]

= 144 + 22 + 176

= 342 g/mol

(iii) (NH4)2SO4 -

[(2 x 14) + (8 x 1) + (1 x 32) + (4 x 16)]

= 28 + 8 + 32 + 64

= 132 g/mol

(iv) FeCl3 -

[(1 x 56) + (3 x 35.5)]

= 56 + 106.5

= 162.5 g/mol