Question

A chemist prepares a solution of potassium dichromate K₂Cr₂O₇ by measuring out 22 g of potassium dichromate into a 150 mL volumetric flask and filling the flask to the mark with water.Calculate the concentration in mol/L of the chemist's potassium dichromate solution. Round your answer to 2 significant digits.

Answer 1

To calculate the concentration of the chemist's potassium dichromate solution, divide the moles of solute by the volume of the solution in liters. The concentration is 0.50 mol/L.

Step-by-step explanation:

To calculate the concentration in mol/L of the chemist's potassium dichromate solution, we need to use the formula:

Concentration (mol/L) = moles of solute / volume of solution (L)

First, we need to calculate the moles of potassium dichromate. The molar mass of K₂Cr₂O₇ is 294.18 g/mol, so:

Moles of K₂Cr₂O₇ = mass of K₂Cr₂O₇ / molar mass of K₂Cr₂O₇

= 22 g / 294.18 g/mol

= 0.0748 mol

Next, we need to convert the volume of the solution to liters. 150 mL is equal to 0.150 L.

Finally, we can calculate the concentration:

Concentration = 0.0748 mol / 0.150 L

= 0.499 mol/L

Rounding to 2 significant digits, the concentration of the potassium dichromate solution is 0.50 mol/L.