# What molar quantity of water molecules are in a 50*g mass of Ca(NO_3)_2*4H_2O?

Approx. $0.9 \cdot m o l$
$\text{Moles of } C a {\left(N {O}_{3}\right)}_{2} \cdot 4 {H}_{2} O$ $=$ $\frac{50.0 \cdot g}{236.15 \cdot g \cdot m o {l}^{-} 1}$ $=$ $0.212 \cdot m o l$.
Thus, since it is a tetrahydrate, there $4 \times 0.212 \cdot m o l \text{ water molecules}$