Question

part 1 of 3
you have been asked to make 250.0 ml of a 0.100 m solution of calcium nitrate.
calculate the mass (in g) of solid calcium nitrate needed to make the solution. round your answer to 3 significant digits.
□ g

Explanation:

Step1: Convert volume to liters

$250.0\ \text{mL} = \frac{250.0}{1000} = 0.2500\ \text{L}$

Step2: Calculate moles of solute

Moles = Molarity × Volume
$\text{Moles of } \text{Ca(NO}_3\text{)}_2 = 0.100\ \text{mol/L} \times 0.2500\ \text{L} = 0.0250\ \text{mol}$

Step3: Find molar mass of $\text{Ca(NO}_3\text{)}_2$

Molar mass = $40.08 + 2\times(14.01 + 3\times16.00) = 164.10\ \text{g/mol}$

Step4: Calculate mass of solute

Mass = Moles × Molar mass
$\text{Mass} = 0.0250\ \text{mol} \times 164.10\ \text{g/mol} = 4.1025\ \text{g}$

Step5: Round to 3 significant digits

Round $4.1025\ \text{g}$ to 3 sig figs

Answer:

$4.10\ \text{g}$