Question

How many grams of potassium dichromate are required to prepare a 250 mL solution with a concentration of 2.16 M?

A) 60.48 g
B) 54.00 g
C) 108.00 g
D) 120.96 g

Answer 1

The calculated mass of potassium dichromate needed for a 250 mL solution with a concentration of 2.16 M is 158.856 g; however, this result does not match any of the multiple-choice options provided.

Step-by-step explanation:

To calculate the mass of potassium dichromate (K₂Cr₂O₇) required to prepare a 250 mL solution at a concentration of 2.16 M, we first need to know the molar mass of K₂Cr₂O₇, which is approximately 294.18 g/mol. Given that 1 liter of solution is equivalent to 1000 mL, we can calculate as follows:

Molarity (M) = moles/volume (L), so moles = Molarity × volume (L).

First, we find the moles of K₂Cr₂O₇:
2.16 M × 0.250 L = 0.54 moles.

Then, we convert moles to grams:
0.54 moles × 294.18 g/mol = 158.856 g.