Определите Массовую долю элемента в следуйщих веществах?

KNO3

Ca(H2PO4)2

Ca3(PO4)2 

Mr(KNO3)=39+14+(16*3)=101 

w(K)=39/101*100=39% 

w(N) =14/101*100=14% 

w(O3)=48/101*100=47%  

Mr(Ca(H2PO4)2)=40+(2+31+64)*2= 234 

w(Ca)=40/234*100%=17%

w(H2)=2*2/234*100%=2%

w(P)=31*2/234*100%=26%

w(O4)=64*2/234*100%=55%

Mr(Ca3(PO4)2)=120+(31+64)*2=310 

w(Ca3)=120/310*100%=39%

w(P)=31*2/310*100%=20%

w(O4)=64*2/310*100%=41%