Chapter 23 quizlet

Cards (27)

  • State the use of an electrochemical cells
    It allows the transfer of electrons to be captured in an electrical circuit
  • What is an electrode potential a measure of?
    The reactivity of a metal and their powers as a reducing agent.
  • What is an electrode?
    Any reversible system containing chemical species undergoing a redox reaction
  • What is the use of the standard hydrogen electrode?
    It allows us to measure the oxidising/ reducing ability of another half cell
  • What equilibrium occurs in the standard hydrogen electrode?
    2H+ (aq) + 2e- = H2(g)
  • Name the components of the standard hydrogen electrode.
    100kPa H2 gas, 1moldm^(-3) HCl solution, 298K, platinum electrode
  • When drawing a half cell of metal ions, what is the electrode?
    Platinum
  • What are the general components of a full cell?
    Voltmeter, salt bridge, two half cells
  • What is the purpose of the salt bridge?
    completes electrical circuit without introducing more metal into the system
  • What is the salt bridge?
    a glass tube filled with an electrolyte e.g KNO3
  • Define standard electrode potential.
    The voltage measured when the name electrode is connected to the standard hydrogen electrode at 298K under 100kPa with solutions of 1.00moldm^(-3)
  • How would you calculate cell potential from emf?
    cell potential= more positive - more negative E°
  • What does a more positive standard potential mean in terms of oxidising or reducing agents?

    Its a more powerful oxidising agent and that chemical is most likely to be reduced
  • For a reaction to be feasible, what must its cell voltage be?
    Positive
  • How would you determine if a reaction is feasible or not?
    Write down the proposed reaction regardless of E°.

    Then calculate cell voltage based on the electrochemical series and which redox reaction is going forwards.

    A positive cell voltage is feasible.
  • In a feasible reaction, how would you explain why a specific chemical was able to be reduced?
    Its a more powerful oxidising agent and had a higher
    The backwards reaction had a species that was a more powerful reducing agent
  • Why might some feasible reactions still not take place?
    A high Ea results in a really slow rate of reaction

    Standard conditions in actuality are different so the E° values change and therefore the cell voltage changes and might become negative
  • in a sequence of redox reaction, how would you determine what the final species is?
    Order the reactions in steps i.e products of one reaction is the reactant of the next
    Work out all feasible reactions
    The non feasible reaction's reactant is the final species
  • From a group of compounds and their SEPS, how would you find the most powerful oxidising agent and most powerful reducing agent?
    Oxidising; most positive SEP
    Reducing: most negative SEP
  • How would you find the change in amount of substance from SEPs?
    1. Construct half equations of each electrode
    2. The electrode that loses mass is the backwards reaction/ oxidation
    3. Construct a full equation
    4. Use stoichiometry to find the answer
  • What would you call a single use storage cell?
    Primary use cells
  • What state are the species in inside a single use storage cell?
    A solid paste.
  • What is discharging in terms of electrical current and SEPs?
    Producing an electrical current
    more positive SEP -- more negative SEP
  • What is charging in terms of electrical current and SEPs?
    Applying a voltage to reverse any chemical change
    i.e. the more negative SEP goes forward
  • How does a fuel cell create a voltage?
    uses the energy generated from the reaction between a fuel and oxygen
  • List some differences between a storage cell and a fuel cell
    Operates continously under a supply of oxygen

    storage cells stop when the redox reaction does

    Very little pollution
  • What are the components of a fuel cell?
    an electrolyte
    a catalyst
    a negative and positive electrode