Electrochemistry

• What is a half cell in an electrochemical cell?

  One half of an electrochemical cell
• What can a half cell be constructed from?

  A metal dipped in its ions or platinum electrode
• What happens when a metal comes into contact with its ions in a half cell?

  A reaction occurs and reaches equilibrium
• What is the equilibrium reaction involving Fe ions?

  Fe²⁺ + 2 electrons ⇌ Fe
• Why is platinum used as an electrode in some half cells?

  It is inert and has good electrical conductivity
• What is created when two different half cells are joined together?

  An electrochemical cell
• What is the role of a voltmeter in an electrochemical cell?

  To measure the potential difference
• What do electrons flow from in an electrochemical cell?

  A more reactive metal to a less reactive one
• What happens to the zinc electrode in a zinc half cell?

  It gets thinner as zinc converts to ions
• What occurs at the copper electrode in an electrochemical cell?

  Copper ions accept electrons and form copper metal
• What is the purpose of the salt bridge in an electrochemical cell?

  To complete the circuit and balance charges
• What does the salt bridge contain?

  Potassium nitrate solution
• What is the standard hydrogen electrode used for?

  To measure standard electrode potential
• What is the E_naught value of the standard hydrogen electrode?

  Zero volts
• What are the standard conditions for measuring electrode potentials?

  298 K and 100 kPa
• Why are electrode potentials measured against the standard hydrogen electrode?

  To provide a universal reference for comparison
• What must be present in the solution for the standard hydrogen electrode setup?

  1 mole per dm³ of H⁺ ions
• What is the significance of the electrochemical series?

  It shows the relative reactivity of half cells
• How do you determine which half cell undergoes oxidation and which undergoes reduction?

  By comparing their electrode potential values
• What acronym helps remember the relationship between oxidation and reduction?

  Oil-Rig (Oxidation Is Loss, Reduction Is Gain)
• What happens to the half equations when combining them for a full cell reaction?

  Oxidation equation is reversed, reduction remains
• What is the overall reaction when zinc and copper half cells are combined?

  Zn + Cu²⁺ → Zn²⁺ + Cu
• What does the term 'redox reaction' refer to?

  Reduction and oxidation occurring simultaneously
• What is the role of the inert platinum electrode in the standard hydrogen electrode setup?

  To conduct electricity without reacting
• How do the electrode potentials of half cells relate to their reactivity?

  More negative potentials indicate higher reactivity
• What is the importance of having a reference electrode in electrochemistry?

  It allows for consistent comparison of potentials
• What is the significance of the term 'EMF' in electrochemical cells?

  It refers to the electromotive force
• What does the term 'oxidation' mean in electrochemistry?

  Loss of electrons from a substance
• What does the term 'reduction' mean in electrochemistry?

  Gain of electrons by a substance
• How does the setup of a standard hydrogen electrode facilitate the measurement of electrode potentials?

  It provides a stable reference point for comparison
• What is the relationship between the reactivity of metals and their position in the electrochemical series?

  More reactive metals have more negative potentials
• What is the purpose of using a saturated potassium nitrate solution in the salt bridge?

  To allow ions to flow and balance charges
• What happens to the zinc electrode during the oxidation process?

  It loses mass as zinc ions enter solution
• What happens to the copper electrode during the reduction process?

  It gains mass as copper metal is deposited
• How do you identify which half cell is oxidized and which is reduced?

  By comparing their electrode potential values
• What is the significance of the equilibrium established in a half cell?

  It indicates the balance between ions and metal
• What is the general setup for a standard hydrogen electrode?

  Platinum electrode with hydrogen gas at standard conditions
• What is the role of the inert platinum electrode in the standard hydrogen electrode setup?

  To conduct electricity without participating in reactions
• How does the electrochemical series help in predicting the direction of electron flow?

  It ranks half cells by their tendency to gain electrons
• What is the importance of the salt bridge in maintaining electrochemical cell function?

  It prevents charge buildup and maintains flow