Question
What mass of silver (Atomic mass = 108 g/mol) deposited by a quantity of electricity which displaces 5600 mL of O _2 at STP ?
What mass of silver (Atomic mass = 108 g/mol) deposited by a quantity of electricity which displaces 5600 mL of O _2 at STP ?
D. 108.0\ g
Volume of O_2 displaced at STP = 5600 mL = 5.6 L. Moles of O_2 = 5.6 22.4 = 0.25 mol. The reaction for the liberation of O_2 is: 2H_2O O_2 + 4H^+ + 4e^- Number of moles of electrons (Faradays) required for 0.25 mol of O_2 = 0.25 4 = 1 F. The reaction for the deposition of silver is: Ag^+ + e^- Ag Since 1 F of electricity deposits 1 mole of Ag, the mass of Ag deposited is: 1 108 = 108.0 g. Answer: 108.0\ g
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