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Gibbs Free Energy quiz

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  • What does a negative value of Gibbs free energy (ΔG) indicate about a reaction?
    A negative ΔG means the reaction is spontaneous.
  • What is the equation for Gibbs free energy?
    ΔG = ΔH - TΔS, where ΔH is enthalpy, T is temperature, and ΔS is entropy.
  • What does it mean if ΔG is zero for a reaction?
    If ΔG is zero, the reaction is at equilibrium.
  • How does the equilibrium constant (K) relate to reaction spontaneity?
    If K > 1, the reaction is spontaneous; if K < 1, it is non-spontaneous.
  • What does a positive ΔG value indicate about a chemical reaction?
    A positive ΔG means the reaction is non-spontaneous.
  • What is the relationship between ΔG and K at equilibrium?
    At equilibrium, ΔG is zero and K equals 1.
  • If ΔH and ΔS are both positive, when is the reaction spontaneous?
    The reaction is spontaneous at high temperatures.
  • If ΔH and ΔS are both negative, when is the reaction spontaneous?
    The reaction is spontaneous at low temperatures.
  • What happens if ΔH is positive and ΔS is negative?
    The reaction is always non-spontaneous.
  • What happens if ΔH is negative and ΔS is positive?
    The reaction is always spontaneous.
  • How can you predict reaction spontaneity if the sign of ΔG is unknown?
    You can use the signs of ΔH and ΔS to predict spontaneity.
  • What does it mean if the equilibrium constant K is less than 1?
    It means the reaction is non-spontaneous and reactants dominate.
  • What does it mean if the equilibrium constant K is greater than 1?
    It means the reaction is spontaneous and products dominate.
  • What does the term 'spontaneous' mean in the context of chemical reactions?
    It means the reaction can proceed without external input of energy.
  • How do the signs of ΔH and ΔS affect the temperature dependence of spontaneity?
    If both are positive, spontaneity increases with temperature; if both are negative, spontaneity increases as temperature decreases.