Question

A metal chloride contains 55.0% of chlorine by weight 100 mL vapours of the metal chloride at STP weight 0.57g. The molecular formula of the metal chloride is

• A. MC13
• B. MC12
• C. MCI
• D. MC14

Answer 1

Answer: (B)

MC12

Answer 2

1. Calculate the molar mass of the metal chloride: Molar Mass = (Weight of vapor / Volume of vapor) * Molar Volume at STP Molar Mass = (0.57 g / 100 mL) * 22400 mL/mol = 127.68 g/mol

2. Calculate the mass of chlorine in one mole: Mass of Cl per mole = Molar Mass * (% of Cl / 100) Mass of Cl per mole = 127.68 g/mol * (55.0 / 100) = 70.224 g/mol

3. Determine the number of chlorine atoms: Number of Cl atoms = Mass of Cl per mole / Atomic mass of Cl Number of Cl atoms = 70.224 g/mol / 35.5 g/mol ≈ 1.978 ≈ 2

4. The molecular formula is MCl₂.