a)
CaCO3 --toC--> CaO + CO2
CaO + H2SO4 --> CaSO4 + H2O
b)
m g 272 g
CaO + H2SO4 --> CaSO4 + H2O
56 136
=> m = 56x272/136
= 112 g CaO
m.pura 112
CaCO3 --toC--> CaO + CO2
100 56
=> m.pura = 100x112/56
= 200 g CaCO3 pur
200 g CaCO3 ........................ 80% pur
m.ip .......................................... 100%
=.m.ip = 200x100/80
= 250 g CaCO3 impur