Bo giải nghen!!!
1. ta có;
n H2SO4=Cm. V=4.5=20(mol)
=>m H2SO4=n.m=20.98=1960(g)
=>m dd H2SO4=m H2SO4. 100:C%=1960 . 100:98=2000(g)
=>V dd H2SO4=m:D=2000:1,84=1087(ml)
2. ta có!!!!
4P+5O2 =>2P2O5
P2O5+3H2O=>2H3PO4
gọi n P =x=>n P2O5=2/4. x=>n H3PO4=x
ta có:m H2O=V.D=500.1=500(g)
=>m dd =500+71x
=>m H3PO4=mdd. C% :100
=>100. 98x=(500+98x).24,5
=>x=1,52
=>a=1,52.31=47,12