A 35 mL sample of concentrated H3PO4 (14.7M) is diluted to a final volume of 250 mL. a) what is the M of the final solution? b) How much solvent is added to the original solution?

1 Answer
Aug 6, 2017

Answer:

Final concentration.....#~=2*mol*L^-1#

Explanation:

#a.# #"Molarity"="Moles of solute"/"Volume of solution"#....and thus.....

#"Moles of solute"="Molarity"xx"Volume"#.....we gots......

#(35*mLxx10^-3*L*mL^-1xx14.7*mol*L^-1)/(250*mLxx10^-3*L*mL^-1)#

#=2.058*mol*L^-1# #"with respect to phosphoric acid."#

#b.# We assume, reasonably that the volumes ARE additive; i.e. we started with an aqueous solution of #35*mL# volume and we add approx. #215*mL# of water to make it up to a #250*mL# volume.