Question

How many moles of KF are contained in 244 mL of 0.135 m KF solution? The density of the solution is 1.22 g/mL.

Answer 1

Do you mean 0.135m or do you mean 0.135M?

Answer 2

0.135m

Answer 3

I actually was able to figure it out

Answer 4

I would do this.
Convert 0.135m to ?M first.
Take 1000 mL of 0.135m, it will contain 0.135 mols KF. How many grams is that?
That's 0.135 x molar mass KF = about 7.8g(but that's an estimate and you should redo this and all of the other calculations that follow for they are estimates also). mass of the solution then is 1000 + 7.8 = about 1007.8 grams. What's the volume? That's v = m/d = 1007.8/1.22 = about 0.860 L or
0.135/0.860 = about 0.16 M.
Then mols KF = M x L = ?

Answer 5

How many moles of KF are contained in 258.6 mL of 0.0296 M KF solution?

Answer 6

Using the formula n=CV (n=# of moles, C=moles/L, V=volume in L) we first convert the mL into L (since the formula requires).

258.6ml/1000ml/L (1000ml=L) = .02586 L

The 0.0296 M KF is the moles/L.

so now we multiple the volume and the mole concentration
(0.02586 L) (0.0296 mol/L) = 0.000765456

which turns into 7.65 x 10^-3 Moles of KF in 258.6 mL