Question

A chemist must prepare 700.mL of 1.00M aqueous calcium bromide CaBr2 working solution. He'll do this by pouring out some 1.95M aqueous calcium bromide stock solution into a graduated cylinder and diluting it with distilled water. Calculate the volume in mL of the calcium bromide stock solution that the chemist should pour out. Be sure your answer has the correct number of significant digits.

Answer 1

Answer:

359. mL is the volume of the calcium bromide stock solution that the chemist should pour out.

Explanation:

Molarity of the calcium bromide solution= $M_1=1.95 M$

Volume of calcium bromide solution to be diluted = $V_1=?$

Molarity of the calcium bromide solution after dilution = $M_2=1.00 M$

Volume of calcium bromide solution after dilution = $V_2=700. mL$

Dilution eqaution is given as:

$M_1V_1=M_2V_2$

$V_1=\frac{M_2V_2}{M_1}$

$=\frac{1.00M\times 700. mL}{1.95 M}=358.97 mL\approx 359. mL$

359. mL is the volume of the calcium bromide stock solution that the chemist should pour out.