How to prepare 4L of 0.02 M KMnO4?

Question

Please explain every step. Thank you.

Answer 1

0.02 mole/L x 4 L x 158 g/mole = 12.6 g

Explanation:

0.02 M means 0.02 moles of KMnO4 per liter

You want 4 liters, so multiply that by 4

To get mass, you multiply the moles times the molar mass of KMnO4 which is 158 g/mole. The answer of 12.6 grams has 3 sig figs, and if you are required to use correct sig figs you would round the answer to 10. grams.