Question

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

Answer 1

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.