help-ap chem question-almost done?

Question

could someone please help me solve this? im almost there i just dont know the last step.
a person suffering from hyponatremia has a sodium ion concentration in the blood of 0.118 M and a total blood volume of 4.6L. what mass of nacl would need to be added to the blood to bring the sodium ion concentration up to 0.138M assuming no change in blood volume?
so heres what i did:
found the moles Na in the 0.118 solution: 0.543 moles
found the moles in the 0.138 solution- 0.635 moles
found the difference b/w the quantities: 0.092 moles
found that to be 2.12 g. but thats only Na. how do i get NaCl?
please help, i wont go to bed til i get this.

Answer 1

Sorry I just see this problem---I wish you get some rest.
Notice that 0.092 Mol Na+ contains 0.092 Mol Na+ (of course)
but 0.092 Mol NaCl also contains 0.092 Mol Na+, did you see it?
Since the formula mass of NaCl is: 58.442 g/mol, the result is:
0.092 mol * 58.442 g/mol = 5.4 g.