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What volume of a 0.100 M K2Cr2O7 solution contains 73.5 g of K2Cr2O7?

A) 250 mL
B) 500 mL
C) 1000 mL
D) 2000 mL

1 Answer

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Final answer:

To determine the volume of a 0.100 M K2Cr2O7 solution that contains 73.5 g of K2Cr2O7, we calculate the moles of K2Cr2O7 and then divide by the molarity, giving us a volume of 2.5 liters or 2500 mL.

Step-by-step explanation:

A student asked what volume of a 0.100 M K2Cr2O7 solution contains 73.5 g of K2Cr2O7. To find the answer, we first need to calculate the number of moles of potassium dichromate in 73.5 g.

The molar mass of K2Cr2O7 is approximately 294.18 g/mol. Using the formula:


Number of moles = mass (g) / molar mass (g/mol),

we get:

Number of moles of K2Cr2O7 = 73.5 g / 294.18 g/mol ≈ 0.25 mol.

Since the solution's molarity (M) is the number of moles of solute per liter of solution, we can use the formula:

Molarity (M) = moles of solute / volume of solution in liters,

to find the volume:

Volume of solution = moles of solute / molarity (M) = 0.25 mol / 0.100 M = 2.5 L or 2500 mL.

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