\(a.CaCO_3-^{t^o}\rightarrow CaO+CO_2\left(1\right)\\ CaO+2HNO_3\rightarrow Ca\left(NO_3\right)_2+H_2O\left(2\right)\\ b.n_{HNO_3}=1,5.0,2=0,3\left(mol\right)\\ TheoPT\left(2\right)n_{CaO}=n_{Ca\left(NO_3\right)_2}=\dfrac{1}{2}n_{HNO_3}=0,15\left(mol\right)\\ TheoPT\left(1\right):n_{CaCO3}=n_{CaO}=0,15\left(mol\right)\\ \Rightarrow m=0,15.100=15\left(g\right)\\ m_{Ca\left(NO_3\right)_2}=0,15.164=24,6\left(g\right)\)