m.impura = 400 g , puritatea p% = 100%pur - 20% impuritati = 80%
p% = m.px100/m.ip => m.p = m.ipxp%/100
= 400x80/100 = 320 g CaCO3 pur
320 g md V L
CaCO3 + H2SO4 => CaSO4 + H2CO3
100 98 22,4
=> md = 320x98/100 = 313,6 g H2SO4
stim ca c% = mdx100/ms => ms = mdx100/c%
= 313,6x100/50 = 627,2 g sol H2SO4
=> V = 320x22,4/100 = 71,68 L H2CO3