Worksheet: Electroplating and Coulometry
In this worksheet, we will practice calculating the molar mass of a material from the electroplating current and rate of deposition.
The atomic mass of an aqueous metal ion can be estimated by electroplating the metal onto a cathode and comparing the current in the electrolytic cell to the mass of metal deposited. Which of the following effects could not cause the atomic mass of the metal to be underestimated?
- AThe cathode material has more negative electrode potential than the dissolved metal.
- BHydrogen gas is also produced at the cathode of the cell.
- CThe oxidation state of the dissolved metal is higher than expected.
- DThe concentration of the dissolved metal is higher than expected.
- ESome of the deposited metal breaks away from the cathode.
The atomic mass of an aqueous metal ion is estimated by electroplating the metal onto a cathode and comparing the current in the electrolytic cell to the mass of metal deposited. A student guesses that the oxidation state of the metal ion is +2. In reality, the oxidation state of the metal ion is +4. How does the calculated atomic mass compare to the true atomic mass?
- AThe calculated mass is half the true mass.
- BThe calculated mass is one-quarter of the true mass.
- CThe calculated mass is double the true mass.
- DThe calculated mass is four times the true mass.
- EThe calculated mass is equal to the true mass.
After the electrolysis of an aqueous solution of copper(II) sulfate, a deposit of 0.50 g of copper is left on the cathode.
How many moles of electrons are required to generate this deposit of copper?
- A mol
- B mol
- C mol
- D mol
- E mol
Taking the charge of an electron to be C, what is the total charge required to produce this deposit?
- A C
- B C
- C C
- D C
- E C