Question

In this lab, you will be making solutions of potassium permanganate (KMnO4), which has a formula weight of 158.04 g/mole. Remember to show your calculations and include tne Correct unnits in your answers
a) How many grams of KMnO4 would you need to make 1 L of a 2M solution?
b) How many grams of KMnO4 would you need to make 350 mL of a 0.75 M solution?
c) How many grams of KMnO4 would you need to make 80 mL of a 0.01 M solution?

Answer 1

Answer:

A. Mass of KMnO₄ = 316.08 g

B. Mass of KMnO₄ = 41.49 g

C. Mass of KMnO₄ = 0.13 g.

Explanation:

A. Determination of the mass of KMnO₄

We'll begin by determining the number of mole of KMnO₄ in the solution. This can be obtained as follow:

Volume = 1 L

Molarity = 2 M

Mole of KMnO₄ =?

Mole = Molarity × Volume

Mole of KMnO₄ = 2 × 1

Mole of KMnO₄ = 2 moles

Finally, we shall determine the mass of KMnO₄. This can be obtained as follow:

Mole of KMnO₄ = 2 moles

Molar mass of KMnO₄ = 158.04 g/mole

Mass of KMnO₄ =?

Mass = mole × molar mass

Mass of KMnO₄ = 2 × 158.04

Mass of KMnO₄ = 316.08 g

B. Determination of the mass of KMnO₄

We'll begin by determining the number of mole of KMnO₄ in the solution. This can be obtained as follow:

Volume = 350 mL = 350/1000 = 0.35 L

Molarity = 0.75 M

Mole of KMnO₄ =?

Mole = Molarity × Volume

Mole of KMnO₄ = 0.75 × 0.35

Mole of KMnO₄ = 0.2625 mole

Finally, we shall determine the mass of KMnO₄. This can be obtained as follow:

Mole of KMnO₄ = 0.2625 mole

Molar mass of KMnO₄ = 158.04 g/mole

Mass of KMnO₄ =?

Mass = mole × molar mass

Mass of KMnO₄ = 0.2625 × 158.04

Mass of KMnO₄ = 41.49 g

C. Determination of the mass of KMnO₄

We'll begin by determining the number of mole of KMnO₄ in the solution. This can be obtained as follow:

Volume = 80 mL = 80/1000 = 0.08 L

Molarity = 0.01 M

Mole of KMnO₄ =?

Mole = Molarity × Volume

Mole of KMnO₄ = 0.01 × 0.08

Mole of KMnO₄ = 0.0008 mole

Finally, we shall determine the mass of KMnO₄. This can be obtained as follow:

Mole of KMnO₄ = 0.0008 mole

Molar mass of KMnO₄ = 158.04 g/mole

Mass of KMnO₄ =?

Mass = mole × molar mass

Mass of KMnO₄ = 0.0008 × 158.04

Mass of KMnO₄ = 0.13 g