Question

You’ve just started a new job in the laboratory of the Food and Drug Administration. Your supervisor asks you to prepare a 1.50-M solution of aqueous potassium permanganate, KMnO4. What mass of KMnO4 will you need to prepare 500 mL of this solution?

Answer 1

Answer: 118.5 grams

Step-by-step explanation:

Molarity is defined as the number of moles of solute dissolved per liter of the solution.

`Molarity=(n* 1000)/(V_s)`

where,

n= moles of solute

`V_s` = volume of solution in ml = 500 ml

`1.50=(moles* 1000)/(500ml)`

moles = 0.75

moles of solute =
`\frac{\text {given mass}}{\text {molar mass}}`

0.75 =
`\frac{\text {given mass}}{158g/mol}`

mass of
`KMnO_4` = 118.5 grams

Thus mass of
`KMnO_4` needed to prepare 500 mL of this solution iis 118.5 grams