A solution is prepared by dissolving 23.7 g of CaCl2 in 375 g of water. The density of the resulting
solution is 1.05 g/mL. The concentration of Cl- in this solution is __________ M.
can someone help me? how do i get to M?
23.7/molar mass CaCl2 = moles CaCl2
moles Cl^- = 2 times that.
Convert 3675 g water to liters using the density. Then M = mols/L.
1.12?
To find the concentration of Cl- in the solution, you need to first calculate the number of moles of CaCl2 dissolved in the solution. Then, you can use this information to determine the concentration in moles per liter (M).
Here are the step-by-step calculations:
Step 1: Calculate the number of moles of CaCl2
To do this, you will use the molar mass of CaCl2, which is calculated by adding the atomic masses of calcium (Ca) and chlorine (Cl).
Molar mass of CaCl2 = 40.08 g/mol (for Ca) + (2 x 35.45 g/mol) (for Cl)
= 40.08 g/mol + 70.90 g/mol
= 110.98 g/mol
Moles of CaCl2 = mass / molar mass
= 23.7 g / 110.98 g/mol
= 0.2136 mol (rounded to 4 decimal places)
Step 2: Calculate the volume of the solution
To do this, you will divide the mass of the solution (375 g) by its density (1.05 g/mL) to get the volume in milliliters (mL). Then, you convert it to liters (L) by dividing by 1000.
Volume of solution = mass / density
= 375 g / 1.05 g/mL
= 357.1429 mL (rounded to 4 decimal places)
Volume of solution in liters = 357.1429 mL / 1000
= 0.3571 L (rounded to 4 decimal places)
Step 3: Calculate the concentration of Cl- in moles per liter (M)
The concentration (Molarity) is defined as the number of moles of solute per liter of solution. In this case, since CaCl2 dissociates into one Ca2+ ion and two Cl- ions, the concentration of Cl- will be twice the concentration of CaCl2.
Concentration of Cl- = Moles of CaCl2 x 2 / Volume of solution in liters
= 0.2136 mol x 2 / 0.3571 L
= 1.194 M (rounded to 3 decimal places)
Therefore, the concentration of Cl- in the solution is approximately 1.194 M.
To find the concentration of Cl- in the solution in units of Molarity (M), you need to follow these steps:
Step 1: Calculate the total volume of the solution.
To do this, divide the total mass of the solution by its density.
Given:
Mass of the solution (mSolution) = 23.7 g CaCl2 + 375 g water = 398.7 g
Density of the solution (dSolution) = 1.05 g/mL
Volume of the solution (vSolution) = mSolution / dSolution
Step 2: Calculate the number of moles of CaCl2.
Given:
Mass of CaCl2 (mCaCl2) = 23.7 g
Molar mass of CaCl2 (Molar_mass_CaCl2) = 40.08 g/mol + 2(35.45 g/mol) = 110.98 g/mol
Number of moles of CaCl2 (nCaCl2) = mCaCl2 / Molar_mass_CaCl2
Step 3: Calculate the concentration of Cl-.
Since each formula unit of CaCl2 dissociates into two chloride ions (Cl-), the moles of Cl- can be calculated as follows:
Number of moles of Cl- (nCl-) = 2 * nCaCl2
Finally, you can calculate the concentration of Cl- by dividing the moles of Cl- by the volume of the solution in liters.
Concentration of Cl- (cCl-) = nCl- / vSolution
Remember to convert the volume of the solution from milliliters to liters before performing the division.
By following these steps, you can find the concentration of Cl- in the given solution.