What is the molarity of a solution in which 13.7 g of calcium chloride is dissolved in water to a final volume of 750.0 mL?
Atomic weight of
Ca : 40
Cl : 35.5
Molecular weight of CaCl2=40+35.5*2=111
Moles=weight in grams/Molecular weight
=13.7/111 = 0.1234 moles
Molarity = 0.1234 moles/750 ml.
=0.165 moles/l
Please check the atomic weights and the calculations.
Also note that units are missing and incorrect in places so that equations do not balance.
Relative Atomic Mass (RAM) of
Ca : 40
Cl : 35.5
Relative Molecular Mass of CaCl2=40+(35.5*2)=111
Moles=mass in grams/RAM
=13.7 g/111 g mol^-1
= 0.1234 mol
Molarity of solution = 0.1234 mol/0.7500 l.
=0.165 mol/l
or 0.165 M
Thank you Dr. Russ.
To find the molarity of a solution, we need to know the number of moles of solute and the volume of the solution.
First, let's calculate the number of moles of calcium chloride (CaCl2) in the given mass of 13.7 g. To do this, we need to know the molar mass of calcium chloride, which is the sum of the atomic masses of its constituent elements.
The atomic mass of calcium (Ca) is 40.08 g/mol, and the atomic mass of chlorine (Cl) is 35.45 g/mol. Since calcium chloride has two chlorine atoms, we multiply the atomic mass of chlorine by 2.
Molar mass of CaCl2 = (40.08 g/mol) + 2 * (35.45 g/mol)
= 40.08 g/mol + 70.9 g/mol
= 110.98 g/mol
Next, let's calculate the number of moles of calcium chloride using the given mass and molar mass.
Number of moles of CaCl2 = Mass of CaCl2 / Molar mass of CaCl2
= 13.7 g / 110.98 g/mol
Now, let's calculate the volume of the solution in liters. Since the volume is given in milliliters, we divide it by 1000 to convert it to liters.
Volume of solution = 750.0 mL / 1000
= 0.750 L
Finally, we can calculate the molarity (M) of the solution using the formula:
Molarity (M) = Number of moles of solute / Volume of solution (in liters)
Molarity (M) = (13.7 g / 110.98 g/mol) / 0.750 L
Now, let's substitute the values and calculate the molarity:
Molarity (M) = 0.123 mol / 0.750 L
≈ 0.164 M
Therefore, the molarity of the solution is approximately 0.164 M.