Question

A chemist prepares a solution of potassium dichromate K2Cr2O7 by measuring out 3.46μmol of potassium dichromate into a 50.mL volumetric flask and filling the flask to the mark with water. Calculate the concentration in /mmolL of the chemist's potassium dichromate solution. Round your answer to 2 significant digits.

Answer 1

Answer: 0.069 mmol/L

Step-by-step explanation:

Molarity of a solution is defined as the number of moles of solute dissolved per Liter of the solution.

`Molarity=(n* 1000)/(V_s)`

where,

n= moles of solute =
`3.46\mu mol` =
`0.001* 3.46=3.46* 10^(-3)mmol`

1micro (µ) = 0.001 milli (m)

`V_s` = volume of solution in ml= 50 ml

`Molarity=(3.46* 10^(-3)* 1000)/(50ml)=0.069mmol/L`

Thus concentration in mmol/L of the chemist's potassium dichromate solution is 0.069.