Question

Calculate the percentage of phosphorus in :

(a) Calcium hydrogen phosphate Ca$(H_{2}P{O}_4{)}_2$

(b) Calcium phosphate $C{a}_3(P{O}_4{)}_2$

Answer 1

(a) Ca$(H_{2}P{O}_4{)}_2$ = 234.05
$P_2$ = 61.94

% of P = $61.94\times 100/234.05$ = 26.46%

(\frac{61.94 \times\ 100}{234.05}\)

(b) The molar mass of $C{a}_3(P{O}_4{)}_2$ is 310.17g/mole

The atomic mass of phosphorus is 30.97g/mole

P%= $\frac{(2\times 30.97)}{310.17}$ $\times 100$
= $\frac{\left(61.94\right)}{310.17}$ $\times 100$
= $0.997$ $\times 100$
= 19.97% of Phosphorous in Calcium phosphate