Question

Calculate the molarity of a solution prepared by dissolving 0.20 mol of KNO3 into enough water to make 250 mL of solution. ______ M

Answer 1

0.8 M

Step-by-step explanation:

The formula is mol divided by liters. Converting 250 ml to .25 liters is important. Dividing .2 by .25 gets the answer. (I swear it’s right but it’s graded wrong so take this with a grain of salt)

Answer 2

0.8M

Step-by-step explanation:

Given parameters:

Number of moles of KNO₃ = 0.2mol

Volume of KNO₃ = 250mL

Unknown:

Molarity of the solution = ?

Solution:

The molarity of a solution is the number of moles in a given volume of a solution;

Molarity =
`(number of moles )/(volume)`

We need to convert the given volume to L;

1000mL = 1L

250mL will give 250 x 10⁻³L = 0.25L

So;

Molarity =
`(0.2)/(0.25)` = 0.8M