Practice with Dilution Calculations IV,

12V

1. What is the initial volume of a 15.0 M stock solution which has been diluted to a final volume of

250.-ml at a concentration of 2.35 M?

THE INITIAL VOLUME OF THE STOCK SOLUTION IS 0.0392 L OR 39.2 mL

Explanation:

To calculate the volume of a solution before dilution, we make use of the dilution formula;

C1 V1 = C2 V2

C1 = the concentration of the stock solution = 15 M

V 1 = the volume of stock solution = ?

C2 = concentartion of final solution = 2.35 M

V2 = volume of final solution = 250 mL = 250/ 1000 = 0.25 L

Rearranging the formula, we obtain;

V1 = C2V2 / C1

V 1 = 2.35 * 0.25 / 15

V1 = 0.5875 / 15

V1 = 0.0392 L

the initial volume of the stock solution is 0.0392 L or 39.2 mL

2fe + 3h2so4 -> fe2(so4)3 + 3h2

it is necessary to balance equations in order to get the proper amount of reactants as well as products in order not to make a miscalculation.

you cannot change the subscripts as that would change the substance itself. for instance, diatomic elements such as h2 only have the subscript two when a gas. another example would be so4, if you were to change the subscript, the element would no longer be sulfate.

we change the coefficients instead as that only changes the number of molecules rather than the substance itself.

hope this !