The formula for finding the molarity of a solute is "Molarity" = frac("moles of solute")("volume of solution")Molarity=moles of solutevolume of solution.
We are already provided with the molarity, but we still need to find the number of moles of solute:
Rightarrow n = frac(m)(M)⇒n=mM
Rightarrow n = frac(6.94 " g")((40.08 + 2 times 35.45) " g mol"^(- 1))⇒n=6.94 g(40.08+2×35.45) g mol−1
Rightarrow n = frac(6.94)(110.98 " mol"^(- 1))⇒n=6.94110.98 mol−1
Rightarrow n = 0.0625⇒n=0.0625 "mol"mol
Then, let's substitute all relevant values into the formula for molarity:
Rightarrow 0.250 "M" = frac(0.0625 " mol")("volume of solution")⇒0.250M=0.0625 molvolume of solution
Rightarrow 0.250 "mol L"^(- 1) = frac(0.0625 " mol")("volume of solution")⇒0.250mol L−1=0.0625 molvolume of solution
Rightarrow "Volume of solution" = frac(0.0625 " mol")(0.250 " mol L"^(- 1))⇒Volume of solution=0.0625 mol0.250 mol L−1
Rightarrow "Volume of solution" = 0.250⇒Volume of solution=0.250 "L"L
therefore "Volume of solution" = 250 "mL"
Therefore, the volume of the calcium chloride solution is 250 "mL".
