52.8 mL of a calcium chloride solution with unknown concentration was treated with phosphoric acid to remove all of the calcium ions in the form of a precipitate. The precipitate was filtered, dried and was found to have the mass of 3.9565 g. What was the concentration of the calcium chloride solution in M?
Convert 3.9565 g Ca3(PO4)2 to moles, then to moles CaCl2, then M = moles CaCl2/L CaCl2.
i got the moles of Ca3(PO4)2=0.01275549 but how do i covert that to moles of CaCl2? using the stoichiometric ratio which is 1:1 or am i doing something wrong
Yes and no. Yes, you use the stoichiometric ratio but it isn't 1:1 is it? I see 3 moles CaCl2 = 1 mole Ca3(PO4)2.
To find the concentration of the calcium chloride solution, we need to use the principles of stoichiometry and molarity.
First, we need to determine the number of moles of calcium ions in the precipitate. We can do this by dividing the mass of the precipitate by its molar mass. The molar mass of calcium is 40.08 g/mol.
Mass of the precipitate = 3.9565 g
Molar mass of calcium = 40.08 g/mol
Number of moles of calcium = Mass of precipitate / Molar mass of calcium
= 3.9565 g / 40.08 g/mol
Next, we need to relate the moles of calcium to the moles of calcium chloride. Calcium chloride has a formula of CaCl2, meaning it contains two chloride ions for every calcium ion. This means that the number of moles of calcium chloride is twice the number of moles of calcium.
Number of moles of calcium chloride = 2 * Number of moles of calcium
Now, we can calculate the volume of the calcium chloride solution using the molarity formula:
Molarity = Number of moles / Volume (in liters)
We are given the volume of the solution as 52.8 mL. To convert this to liters, we divide by 1000:
Volume = 52.8 mL / 1000 mL/L
Finally, we can plug the values into the molarity formula to find the concentration of the calcium chloride solution:
Concentration of calcium chloride = Number of moles of calcium chloride / Volume
Concentration of calcium chloride = (2 * Number of moles of calcium) / (Volume in liters)
Let's calculate it step by step.
First, calculate the number of moles of calcium:
Number of moles of calcium = 3.9565 g / 40.08 g/mol
Next, find the number of moles of calcium chloride:
Number of moles of calcium chloride = 2 * Number of moles of calcium
Now, convert the volume from milliliters to liters:
Volume = 52.8 mL / 1000 mL/L
Finally, calculate the concentration of calcium chloride:
Concentration of calcium chloride = (2 * Number of moles of calcium) / Volume
By following these steps and performing the calculations, you can find the concentration of the calcium chloride solution in M.