\(n_{CO_2}=\dfrac{4.48}{22.4}=0.2\left(mol\right)\)
\(n_{Ca\left(OH\right)_2}=0.3\cdot1=0.3\left(mol\right)\)
\(T=\dfrac{0.2}{0.3}=0.67\rightarrow CaCO_3,Ca\left(OH\right)_2dư\)
\(n_{CaCO_3}=n_{CO_2}=0.2\left(mol\right)\)
\(m=0.2\cdot100=20\left(g\right)\)