Question

In the laboratory you dissolve 15.1 g of zinc acetate in a volumetric flask and add water to a total volume of 250 . mL.

What is the molarity of the solution?

_________ M

Answer 1

Zinc acetate - Zn(CH₃CO₂)₂

$C_m= \frac{m}{M \cdot V}$

C_m - molarity or molar concentration of the solution, M

m - mass of the solute, g

M - molar mass of the solute, g/mol

V - volume of the solution, l

$M(Zn(CH_3CO_2)_2) \approx 1 \cdot 65.38 + 2 \cdot (1 \cdot 12.01 + 3 \cdot 1 + 1 \cdot 12.01 + 2 \cdot 16)=183.42 \; g/mol$

$C_m= \frac{15.1}{183.42 \cdot 0.25} \approx 0.33 \; M$

Answer: 0.33 M.