20.0g of an unknown metal chloride MCl is dissolved in 100 mL of water. If 357 mL of 0.750 M AgNO3 are required to precipitate (as AgCl) all the chloride in the solution, what is the identity of element M?
-
Moles of Ag+ = moles of Cl- = 0.357 L X 0.750 mol/L = 0.268 moles Cl-.
Since the compound has the formula MCl, the moles of chloride = moles of the metal chloride MCl.
So, the molar mass of the metal chloride is:
20.0 g / 0.268 mol = 74.7 g/mol
The molar mass of the metal = 74.7 - 35.4 = 39.3 g/mol
The only metal close is K, potassium.
Since the compound has the formula MCl, the moles of chloride = moles of the metal chloride MCl.
So, the molar mass of the metal chloride is:
20.0 g / 0.268 mol = 74.7 g/mol
The molar mass of the metal = 74.7 - 35.4 = 39.3 g/mol
The only metal close is K, potassium.