Răspuns:
CaCO3 carbonat de calciu
a.) MCaCO3 =40+12+3×16=100g/mol
100gCaCO3...... 40gCa.......12gC.......48gO
100gCaCO3.......xgCa............ygC.......zgO
x=109×40/100=40g
y=100×12/100=12g
z=100×48/100=48g
b.) CaCO3
rm.Ca:C:O=40:12:48=10:3:12
25paetiCaCO3......10partiCa......3partiC......12partiO
100partiCaCO3......xpaetiCa......ypartiC........zpartiO
x=100×10/25=40 părți
y=100×3/25=12 părți
z=100×12/25=48parti