-DACA substanta are 10%impuritati, va avea90% puritate !
-calculez masa de substanta pura
p/100= mp/m,impur; 90/100= mp/22,2===> mp=19,98g CaCO3pur
-ecuatia reactiei de descompunere
1mol................................1mol
CaCO3-----> CaO + CO2
100g................................44g
19,98g..............................m= calculeaza !!
Explicatii M,CaCO3= (40gCa+12gC+3x16gO)/mol=100g/mol,
M,CO2= ( 12gC+2x12gO)/mol=44g/mol