Yo what volume should 5.0g of KCl be diluted in order to prepare a 0.25 M solution?

1 Answer
Mar 22, 2018

0.268L

Explanation:

Given:
Mass = 5.0g of KCl
Concentration = 0.25M KCl
Molar Mass KCl = 74.5513g/mol
Volume = ?

We can use the molarity formula to solve this, which is

"Molarity"="moles of solute"/"litres of solution"

However since we are trying to find the volume, we use the following formula (rearranged):

"Volume"="moles of solute"/"molarity"

Also, our value 5.0g KCl is not in moles quite yet so we convert that in terms of moles of KCl, using the mole formula,

"Moles"="mass"/"molar mass"

n_(KCl)="5.0g"/"74.5513g/mol"

n_(KCl)=0.067067.....mol

Next we plug in the given values into the volume formula.

"Volume"="moles of solute"/"molarity"

V_(KCl)="0.067067.....mol"/"0.25L"

V_(KCl)=0.268...L

:. "5.0 g KCl" should be diluted to "0.268 L" in order to prepare a "0.25 M KCl" solution.