Answer:
The metal is calcium (to form CaCl2)
Explanation:
Step 1: Data given
Mass of sample of an alkaline earth metal chloride = 1.26 grams
Silvernitrate (AgNO3) = in excess
All of the chloride is recovered as 3.26 g of silver chloride.
Step 2: The equation
XCl2 + 2AgNO3 → X(NO3)2+ 2 AgCl
Step 3: Calculate moles AgCl
Moles AgCl = mass AgCl / molar mass AgCl
Moles AgCl = 3.26 grams / 143.32 g/mol
Moles AgCl = 0.0227 moles
Step 4: Calculate moles XCl2
For 1 mol XCl2 we'll have 2 moles AgCl
For 2*0.0227 moles we need 0.0227/2 = 0.01135 moles
Step 5: Calculate molar mass XCl2
Molar mass XCl2 = mass / moles XCl2
Molar mass XCl2 = 1.26 grams / 0.01135 moles
Molar mass XCl2 = 111 g/mol
Step 6: Calculate of metal X
Molar mass X = molar mass XCl2 - molar mass Cl2
Molar mass X = 111 - 70.9 = 40.1 g/mol
The metal is calcium (to form CaCl2)
