moles qn (1 Viewer)

[bos1234]

A total of 10.0g of sodium chloride is weighed out and dissolved in sufficient water to make 200ml of soln. A. 50ml of soln. A is removed and mixed with 250ml of water to make soln. B. Calculate molarity of

soln. A

soln. B

I got the answer to soln. A 0.85mol/l

but cant get B
answer is

0.143mol/l

 

[Aerlinn]

You have 10g NaCl put into 200ml, which is equivalent to 0.171mol.
If that's the amount of mole of solute you have in 200ml, in 50ml you must have 0.171/4= 0.04275mol.
You're adding this 50ml to 250ml water, so you're concentration for solution B would be 0.04275/ 0.3=0.143mol/l

 

[beentherdunthat]

*Faints* NO MORE MOLES PLEASE THIS IS TORTURE!