Question

What is the molal concentration of lead nitrate in 0.726 M `Pb(NO_3)_2`?

density = 1.202 g/ml

Answer 1

`0.755m`

Explanation:

I originally misread the question and thought the user was asking for molar concentration.

`0.0726*mol*331.22g*mol^-1`
`=24.05g*PbNO_3` in `100ml` of `0.725M` solution.

Subtract, density tells us its `1.202g*ml^-1` so,

`120.2g-24.05g=96.15g`

`96.1534g*(1kg)/(1000g)=0.09615kg`

And now we have:

`m=`molality`= (mol)/(kg)`

`m=` `(0.0726*mol)/(0.09615*kg)`

`=` `0.755m`