Question

A chemist prepares a solution of zinc oxalate by measuring out of zinc oxalate into a volumetric flask and filling the flask to the mark with water. Calculate the concentration in of the chemist's zinc oxalate solution. Round your answer to significant digits. 0.0075 umol 450 mL

Answer 1

Answer: The concentration of zinc oxalate is $1.7\times 10^{-11}M$

Explanation:

To calculate the molarity of solution, we use the equation:

$\text{Molarity of the solution}=\frac{\text{Moles of solute}\times 1000}{\text{Volume of solution (in mL)}}$

We are given:

Moles of zinc oxalate = $0.0075\mu mol=7.5\times 10^{-9}mol$    (Conversion factor:  $1mol=10^{6}\mu mol$  )

Volume of solution = 450 mL

Putting values in above equation, we get:

$\text{Molarity of solution}=\frac{7.5\times 10^{-9}\times 1000}{450mL}\\\\\text{Molarity of solution}=1.66\times 10^{-11}M=1.7\times 10^{-11}M$

In case of multiplication and division, the number of significant digits is taken from the value which has least precise significant digits. Here, the least precise number of significant digits are 2.

Hence, the concentration of zinc oxalate is $1.7\times 10^{-11}M$