[samlovessal]

I have 1000 ml of a 0.75 M stock solution of sodium chloride (NaCl).  I need to dilute this to make 250 mL at a concentration of 0.35 M. What volume of 0.75M sodium chloride stock solution do I need to add and what volume of water do I need to add to make up the 250 mL?

Ok so im using the formula civi=c2v2

this is what

(0.75)(1000)=0.35M
((0.75m)(1000ml))/0.35m = 2142.857142 – 1000 = 1142/250 =4.57
Therefore we need to add 1142ml to dilute 1000ml to 0.35 M
116.6 ml to make 250ml of 0.35 M

[Hunter2]

correct for 250 ml, but you dont have to dilute the whole solution.