Question

Sally has constructed a concentration cell to measure Ksp for MCln. She constructs the cell by adding 2 mL of 0.05 M M(NO3)n to one compartment of the microwell plate. She then makes a solution of MCln by adding KCl to M(NO3)n. She adds 6.380 mL of the resulting mixture to a second compartment of the microwell plate.

Sally knows n (the charge on the metal ion) = +2
She has already calculated [Mn+] in the prepared MCln solution using the Nernst equation. [Mn+] = 8.279 M

Required:
How many moles of [Cl-] must be dissolved in that compartment?

Answer 1

0.1056 mole

Step-by-step explanation:

As Sally knows that the charge on the metal ion is n = +2

`$MCl_n=MCl_2$`

In that compartment
`$[M^(n+)]=[m^(2+)]=8.279 \ M$`

The volume of the
`$MCl_n$` taken in that compartment = 6.380 mL

So, the number of moles of
`$M^(2+) = 8.279 * 6.380$`

= 52.82 m mol

= 0.05280 mol

`$MCl_n \rightarrow M^(n+)+nCl^-$`

But n = 2

Therefore, moles of
`$Cl^-$` = 2 x moles of
`$M^(n+)$`

= 2 x 0.05282

= 0.1056 mole