4.3.5 Representation of reactions at electrodes as half equations

• Electrochemistry is the study of chemical reactions that involve the transfer of electrons
• Electrochemistry involves spontaneous reactions, while electrolysis requires electricity.


  True
• The positive electrode in electrolysis where oxidation occurs is called the anode
• The negative electrode in electrolysis where reduction occurs is called the cathode
• In electrolysis, the reaction type is spontaneous.

  False
• The anode is the positive electrode where oxidation occurs.
• Match the half equation type with its location:

  Oxidation ↔️ Anode

  Reduction ↔️ Cathode
• Reduction half equations represent the gain of electrons at the cathode.
• Reduction involves the loss of electrons by a substance.

  False
• In the electrolysis of sodium chloride, the reduction half equation at the cathode is $2Na^ +$$+$$2e^ - \rightarrow 2Na$, which represents the gain of electrons.
• The cathode is the site of reduction.


  True
• What is the primary function of electrodes in electrolysis?

  Electron transfer
• Match the electrode with its function:

  Anode ↔️ Site of oxidation

  Cathode ↔️ Site of reduction
• The oxidation half equation represents the loss of electrons at the anode.


  True
• Match the process with its electron transfer:

  Oxidation ↔️ Loss of electrons

  Reduction ↔️ Gain of electrons
• Write the half equation for the reduction of copper(II) ions to copper metal.

  Cu^{2 + } + 2e^ - \rightarrow Cu</latex>
• In the electrolysis of NaCl, chloride ions are oxidized to chlorine gas at the anode.

  True
• What is the first step to balance the charge in a half equation?

  Identify electron transfer
• Balance the half equation for the reduction of copper(II) ions.

  $Cu^{2 + } +$$2e^ - \rightarrow Cu$
• Electrolysis is the process of using electricity to drive a non-spontaneous chemical reaction
• Electrochemistry generates electricity, while electrolysis requires it.


  True
• The anode in electrolysis facilitates oxidation
• Electrolysis uses electricity to drive a non-spontaneous
• What type of reaction occurs in electrochemistry?

  Spontaneous
• Match the example with the process:

  Electrochemistry ↔️ Batteries

  Electrolysis ↔️ Electroplating
• Electrodes facilitate electron transfer between the circuit and the electrolyte
• What process occurs at the cathode?

  Reduction
• Match the half equation type with its location:

  Oxidation ↔️ Anode

  Reduction ↔️ Cathode
• Oxidation involves the loss of electrons from a substance.


  True
• Where does oxidation occur in the electrolysis of NaCl?

  Anode
• The reduction of $Cu^{2 + }$ ions to $Cu$ metal requires the gain of two
• What is the oxidation half equation for chloride ions at the anode?

  2Cl^ - \rightarrow Cl_{2} + 2e^ -</latex>
• How do you balance the charge in a half equation?

  Add electrons
• Combining half equations requires equating the number of electrons transferred.

  True
• Electrolysis is the process of using electricity to drive a non-spontaneous chemical reaction
• Match the process with its energy role:

  Electrochemistry ↔️ Produces electricity

  Electrolysis ↔️ Consumes electricity
• Order the steps involved in the function of electrodes during electrolysis:

  1️⃣ Electrodes make electrical contact with the electrolyte

  2️⃣ Oxidation occurs at the anode, losing electrons

  3️⃣ Reduction occurs at the cathode, gaining electrons
• Electrolysis requires electricity to drive non-spontaneous reactions.
• The cathode is the negative electrode where reduction occurs.


  True
• Oxidation half equations represent the loss of electrons at the anode.