500 mL of a 0.4 M potassium dichromate contains ________ moles of potassium ions and ________ moles of dichromate ions.

Question

Quizplus · Accepted Answer

The formula for potassium dichromate is K2Cr2O7, indicating two potassium ions (K+) for each dichromate ion (Cr2O7^2-). For a 0.4 M solution, there are 0.4 moles of K2Cr2O7 per liter. Since the volume is 500 mL (0.5 L), the amount of K2Cr2O7 is 0.4 moles/L * 0.5 L = 0.2 moles. Therefore, there are 0.4 moles of potassium ions (since each molecule provides two potassium ions) and 0.2 moles of dichromate ions in 500 mL of the solution.

500 ML of a 0