An unknown metal, M, reacts with excess chlorine to give the metal chloride, MClx. When 0.396 g of t — Stoichiometry / Descriptive Chemistry Chemistry Question
Problem Context
An unknown metal, M, reacts with excess chlorine to give the metal chloride, MClx. When 0.396 g of the chloride is dissolved in water and passed through an anion exchange column charged with hydroxide ions, the solution requires 23.55 mL of 0.195 M HCl for neutralization.
Calculate the number of moles of HCl used in the titration.
Model Answer
0.02355 L HCl × 0.195 mol / L = 0.00459 mol H+ = 0.00459 mol Cl–
Determine the mass of chlorine and the mass of metal in this sample of MClx.
Model Answer
0.00459 mol Cl– × 35.45 g / mol = 0.163 g Cl–
0.396 g MClx - 0.163 g Cl– = 0.233 g M
Assuming that x in MClx is 1, 2 or 3, calculate possible atomic masses for M.
Model Answer
0.396 g MCl - 0.163 g Cl– = 0.233 g × (1 / 0.00459 mol) = 50.8 g/mol
0.396 g MCl2 - 0.163 g Cl– = 0.233 g × (1 / 0.00230 mol) = 101.3 g/mol
0.396 g MCl3 - 0.163 g Cl– = 0.233 g × (1 / 0.00153 mol) = 152.3 g/mol
Use your knowledge of the Periodic Table to write formulas for the possible compounds between chlorine and metals and identify those expected to be stable.
Model Answer
50.8 g·mol–1 most likely V VCl unlikely to be stable
101.3 g·mol–1 most likely Ru RuCl2 stable
152.3 g·mol–1 most likely Eu EuCl3 stable