# Worksheet: Charge Transfer in Electrolysis

In this worksheet, we will practice calculating the total amount of charge transferred during electrochemical processes such as electroplating.

Q1:

What is the charge of a mole of electrons? The charge of a single electron is C .

• A C
• B C
• C C
• D C
• E C

Q2:

The reduction of aluminum ions is described by the ionic half-equation: What charge must be delivered to reduce 200 kg of aluminum ions to aluminum metal? The charge of a single electron is C.

• A C
• B C
• C C
• D C
• E C

Q3:

The reduction of lithium ions can be represented by the ionic half-equation:

How many electrons are required per lithium ion to produce lithium metal?

How many moles of electrons are required to reduce 1.00 g of lithium ions?

How much charge must be delivered to reduce 1.00 g of lithium ions? The charge of a single electron is C.

• A C
• B C
• C C
• D C
• E C

Q4:

How long would it take to reduce 1 mole of to using a current of 33.5 A? Assume the voltage is sufficient to perform the reduction.

Q5:

How long would it take to reduce 1 mole of to using a current of 4.01 A? Assume the voltage is sufficient to perform the reduction.

Q6:

What mass of calcium is produced in the electrolysis of molten if a total charge of C passes through the cell? Assume the voltage is sufficient to perform the reduction and that the efficiency is 100%.

Q7:

What mass of lithium is produced in the electrolysis of molten if a total charge of C passes through the cell? Assume the voltage is sufficient to perform the reduction and that the efficiency is 100%.

Q8:

What mass of aluminum is produced in the electrolysis of molten if a total charge of C passes through the cell? Assume the voltage is sufficient to perform the reduction and that the efficiency is 100%.

Q9:

What mass of chromium is produced in the electrolysis of molten if a total charge of C passes through the cell? Assume the voltage is sufficient to perform the reduction and that the efficiency is 100%.

Q10:

How long would it take to reduce 1 mole of using a current of 1.057 A? Assume the voltage is sufficient to perform the reduction.

Q11:

How long would it take to reduce 1 mole of using a current of 19.8 A? Assume the voltage is sufficient to perform the reduction.

Q12:

In one process used for electroplating silver, a current of 10.23 A was passed through an electrolytic cell for exactly 1 hour.

How many moles of electrons passed through the cell?

What mass of silver was deposited at the cathode?

Q13:

Aluminum metal can be made from aluminum ions by electrolysis. What mass of aluminum metal would be recovered if a current of A passed through the solution for 15.0 minutes? Assume the yield is 100%.

Q14:

In one application, a 0.010 mm layer of chromium must be deposited on a part with a total surface area of 3.3 m2 from a solution containing chromium(III) ions. How long would it take to deposit the layer of chromium if the current was 33.46 A? The density of chromium (metal) is 7.19 g/cm3.

Q15:

The top of a sheet of iron is galvanized to a thickness of 0.100 mm of zinc. The density of zinc is 7.140 g/cm3.

What mass of zinc is required?

If the zinc comes from a solution of and the current is 25.5 A, how long will it take to galvanize the top of the iron?

Q16:

An irregularly shaped metal part made from a particular alloy was galvanized with zinc using a solution. When a current of 2.399 A was used, it took exactly 1 hour to deposit a 0.01323 mm layer of zinc on the part. What was the total surface area of the part? The density of zinc is 7.140 g/cm3. Assume the efficiency is .

Q17:

The current in a circuit is 2.5 A. To 2 significant figures, how many coulombs of charge pass through the circuit in 35 minutes?

• A C
• B88 C
• C4.3 C
• D C
• E14 C

Q18:

If the current in a circuit is 3.5 A, how many moles of electrons pass through the circuit in 45 minutes?

• A mol
• B mol
• C mol
• D mol
• E mol