A solution is prepared by dissolving 23.7g of CaCl2 in 375.0g of water. The density of this solution is 1.05g/mL. determine the concentration (molarity) of Cl in solution.
0.98
To determine the concentration (molarity) of Cl in the solution, we need to first find the moles of CaCl2 and then calculate the moles of Cl.
Step 1: Calculate the moles of CaCl2:
We have the mass of CaCl2, which is 23.7g. To find the moles, we need to divide the mass by the molar mass of CaCl2.
The molar mass of CaCl2 is calculated by adding the atomic masses of each element in the compound:
Calcium (Ca) = 40.08 g/mol (from periodic table)
Chlorine (Cl) = 35.45 g/mol (from periodic table)
Molar mass of CaCl2 = (1 × Ca) + (2 × Cl) = (1 × 40.08 g/mol) + (2 × 35.45 g/mol) = 40.08 g/mol + 70.90 g/mol = 110.98 g/mol
Now, we can calculate the moles of CaCl2:
moles of CaCl2 = mass / molar mass = 23.7g / 110.98 g/mol = 0.2136 mol
Step 2: Determine the moles of Cl:
In CaCl2, there are two moles of Cl for each mole of CaCl2.
moles of Cl = moles of CaCl2 × 2 = 0.2136 mol × 2 = 0.4272 mol
Step 3: Calculate the volume of the solution:
We are given the density of the solution, which is 1.05 g/mL. Using this information, we can determine the volume of the solution.
volume of solution = mass of solution / density = 375.0g / 1.05 g/mL = 357.14 mL
Step 4: Calculate the concentration (molarity):
Molarity (M) is defined as moles of solute divided by liters of solution.
volume of solution needs to be converted from milliliters (mL) to liters (L):
volume of solution = 357.14 mL × (1 L / 1000 mL) = 0.35714 L
Now, we can calculate the molarity of Cl:
molarity of Cl = moles of Cl / volume of solution = 0.4272 mol / 0.35714 L = 1.196 M
Therefore, the concentration (molarity) of Cl in the solution is 1.196 M.