How do I know that the molarity was 8.00 M? How do you use the formula?!?

Question

5.00 mL of concentrated HCL is diluted to give 25.0 mL of 1.60 M HCL. What was the molarity of the concentrated HCL?

The answer is 8.00 M.

The formula is Mi=Mv (i and v are subscripts) but I dont understand how to use it.

Answer 1

i'll give u a better formula: V1*C1=V2*C2
V1 IS THE INITIAL VOLUME
C1 IS THE INITIAL CONCENTRATION (M, N, F, ETC)
V2 IS THE FINAL VOLUME
C2 IS THE FINAL CONCENTRATION

SO...
(5ml)*C1=(25ml)*(1.6M) ---> clear the equation up adn you get
C1= ((25ml)*(1.6M))/(5ML)
RESOLVE THE EQUATION AND THE RESULT IS 8.0 M.
IT APPLIES TO MOST DILUTING PROBLEMS.
HOPE IT HELPS!

Answer 2

The answer is 8.00M
The formula should be M1V1 = M2V2
where M1 is the molarity of the concentrated HCl and V1 is its volume.
M2 is the molarity of the diluted HCl and V2 is it volume

substituting the values into the formula,

(M1)(5 mL) = (1.6M)(25mL)
M1 = 8.00M

Answer 3

x5 = (1.60)(25.0)

Initial molarity times initial volume on one side of the equation.
On the other is the final molarity and final volume.

Why?

Because they must balance out. If you change the volume then the molarity is also changed inversely. More volume, less molarity (think more water per solute then less concentration of solute aka less molarity).

Answer 4

C1 V1= C2 V2

C1 (5ml) = 1.60 (25ml)

(1.60 (25)) /5 = 8

C1= starting concentration
V1= starting volume
C2= ending concentration
V2= ending volume

Answer 5

First determine the number of moles in the final solution (the part in brackets), then divide by the original volume to get the original molarity

[1.6mol/l x 0.025l]/0.005l = 8mol/l or 8 M

Answer 6

M1V1=M2V2 so

M1*25.0ml=5.00ml*1.60

M=.32

that is usually how it is done, I have never heard of that other formula, are you sure the answer is 8.00 M

I personally think it should be .32M

Answer 7

do a titration