Question

lab data
preparation of stock solution
mass of $ce{cuso_{4}·5h_{2}o}$ (g): 3.06
total volume of solution (ml): 100.0
molarity of $ce{cuso_{4}}$ solution (m)
preparation of first diluted solution
molarity of stock $ce{cuso_{4}}$ solution

Explanation:

Step1: Calculate molar mass of $\text{CuSO}_4 \cdot 5\text{H}_2\text{O}$

Molar mass = $63.55 + 32.07 + 4\times16.00 + 5\times(2\times1.01 + 16.00) = 249.72\ \text{g/mol}$

Step2: Calculate moles of solute

$\text{Moles} = \frac{\text{Mass}}{\text{Molar Mass}} = \frac{3.06\ \text{g}}{249.72\ \text{g/mol}} \approx 0.01225\ \text{mol}$

Step3: Convert volume to liters

$\text{Volume} = \frac{100.0\ \text{mL}}{1000} = 0.1000\ \text{L}$

Step4: Calculate molarity of stock solution

$\text{Molarity} = \frac{\text{Moles}}{\text{Volume (L)}} = \frac{0.01225\ \text{mol}}{0.1000\ \text{L}} = 0.1225\ \text{M}$

Answer:

$0.123\ \text{M}$ (rounded to 3 significant figures)