1. the solution is diluted by 5/475 dilution factor i.e. 1/95x
so you can also use this factor to find the initial molarity (M1) by dividing the final molarity (0.1M) with 1/95..i.e. 0.1x95 = 9.5M.
2. c1v1=c2v2 and we are looking for v2 so;
v2=(c1v1)/c2 = (7x16)/2.5 = 44.8mL
i got the same answer with you..if you are in doubt, then you can calculate the dilution factor and use it to determine the final concentration;
so, initial volume is 7mL and final is 44.8mL; dilution factor = 7/44.8 = 0.15625x
multiply this with the initial concentration and see what happens...
if it gives 2.5M then 44.8mL is correct...
hope that helps..
1. What molarity is needed so that 5mL diluted to 475 mL will yield 0.1M?
For this one I used M1V1=M2V2 and got 9.5M just checking to see if I did that right.
2. How much 2.5 HNO3 can be made from 7.0mL of a 16.0M HNO3 soltuion?
I tried using M1V1=M2V2 for this one too but wound up needing 44.8mL. I can't think of another way to try to solve the problem.
2 answers
Oh I think I was just looking at the question the wrong way. I was wondering how I could get 44.8mL from 7.0mL forgetting that the 2.5M solution would need to be diluted. Thanks!