Question

what massof calcium oxide CaO,forms when 25g calcium carbonate CaCO3 decomposes on heating?

Answer 1

Moles of CaCO3 = m/MW= (25g)/(100g/mol) = 0.25 moles
CaCO3 -> CaO + CO2
Coefficients 1 1 1
Moles 0.25 x x

Ratio: CaCO3:CaO
1:1

0.25 moles of CaO formed
Mass CaO = (MW)(moles)= (56g/mol)(0.25)= 14g