help with stoichiometry

[Comatose]

what volume of water is needed to produce a 2M NaCl solution if 2.35g of NaCl are present?
the answer is 20.1ml.
thanks

[b^3]

c=n/v so we need concen. (we have it) and mol
first you need to find mol of NaCl
n(NaCl)=2.35/58.44
=0.0402mol
c=n/v
so v=n/c
v(NaCl)=0.0402/2
=0.0201L
=20.1mL (i.e.*1000 to convert)
Q.E.D

[Comatose]

i understand your working except why is the answer 20.1ml when that answer is the volume of NaCl? i thought its asking for water? whats does Q.E.D mean btw?

[b^3]

The volume of water is the volume of the solution which is the volume of NaCl since it is all in the same solution.
2.35g of NaCl will require 20.1mL of water to be dissolved in to give a solution of 2.0M
And Q.E.D  is quod erat demonstrandum or translated "which was to be demonstrated"
Or memy old teachers modern day version, "Quite easily done", it's something that normally goes at the end of maths proofs, sorry don't write that down.

EDIT: Added wording

[nbhindi]

Or me old teachers modern day version, "Quite easily done", it's something that normally goes at the end of maths proofs, sorry don;t write that down.

Classic

[b^3]

Or me old teachers modern day version, "Quite easily done", it's something that normally goes at the end of maths proofs, sorry don;t write that down.

Classic

That was meant to be "my" and "don't", I'm too tired right now.

[Comatose]

so is that volume (20.1ml) the volume of the whole solution including water, NaCl?

[b^3]

so is that volume (20.1ml) the volume of the whole solution including water, NaCl?

Yes the volume of everything in together, everything in the solution. Sorry about the bad wording above.