Question

How many mmoles of each ion are present in 448 mL of a 0.0840 M solution of K2Cr2O7?

Answer 1

Answer:

mmoles of potassium ion = 75.264 mmoles

mmoles of dichromate ion = 37.632 mmoles

Explanation:

Considering:-

$Molarity=\frac{Moles\ of\ solute}{Volume\ of\ the\ solution}$

$Moles =Molarity \times {Volume\ of\ the\ solution}$

For $K_2Cr_2O_7$ :

Molarity = 0.0840 M

Volume = 448 mL

The mmoles of $K_2Cr_2O_7$ are;-

$Moles =0.0840 \times 448\ mmoles=37.632\ mmoles$

In 1 mmole of $K_2Cr_2O_7$, 2 mmoles of potassium ion and 1 mmole of dichromate ion is present.

In 37.632 mmole of $K_2Cr_2O_7$, 2*37.632 mmoles of potassium ion and 1*37.632 mmole of dichromate ion is present.

mmoles of potassium ion = 75.264 mmoles

mmoles of dichromate ion = 37.632 mmoles