Знайти масову частку у сполуках : 1. k2 cr2, o7; 2.kbr o3; 3.ai(no3)3; fe2(so4)3

K2Cr2O7
Mr(K2Cr2O7)=78+104+112=294
w(K)=78*100/294=26,5%
w(Cr)=104*100/294=35,4%
w(O)=112*100/294=38,1%

Mr(KBrO3)=167
w(K)=39*100/167=23,4%
w(Br)=80*100/167=47,9%
w(O)=48*100/167=28M7%

M(AI(NO3)3=213
w(AI)=27*100/213=12,7%
w(N)=42*100/213=19,7%
w(O)=144*100/213=67,6%

M(Fe2(SO4)3)=400
w(Fe)=112*100/400=28%
w(S)=96*100/400=24%
w(O)=192*100/400=48%