[Geddoe]

You have a solution of 0.2244 M magnesium chloride.
(a) How many moles of solute are contained in 27.03 mL of solution?
(b) How many grams of solute are contained in 27.03 mL of solution?
(c) What volume (in millilitres) of solution is needed to obtain 0.0159 moles of solute?


Here is my work...

(a) M = n / v
n = M * v
= 0.2244 M * (27.03 / 1000mL)

= 0.006065532 mole

(b) M = n / v

n = M * v
= 0.2244 M * (27.03 / 1000mL)
= 0.006065532 mole * (95.21g / 1 MgCl2)
= 0.577499302g


(c)    (1000/0.2244) x 0.0159 mL = 1.13ml


correct?

[UG]

a) and b) looks good.
c) don't know what you're doing there, stick to your formula: M = n / v rearrange to find v.

[Geddoe]

For c ...

you know that there are 0.2244 moles in 1000 mL, so there will be 0.0159 moles in (1000/0.2244) x 0.0159 mL... isn't this logic correct?

[UG]

For c ...
so there will be 0.0159 moles in (1000/0.2244) x 0.0159 mL... isn't this logic correct?

Yes, except that the answer to that is not 1.13 mL