7.6 Free Energy of Dissolution

Cards (45)

  • What does the free energy of dissolution (\(\Delta G_{\text{dissolution}}\)) determine?
    Spontaneity of dissolution
  • What happens when \(\Delta G_{\text{dissolution}}\) is zero?
    The system is at equilibrium
  • What is the equilibrium constant \(K_{sp}\) also known as?
    Solubility product
  • Arrange the following steps to calculate \(\Delta G\) using ΔG=\Delta G =−RTln⁡Ksp - RT\ln K_{sp}:

    1️⃣ Identify \(K_{sp}\) for the compound at the given temperature
    2️⃣ Convert temperature to Kelvin
    3️⃣ Calculate \(\Delta G\) using the equation
  • If \(K_{sp}\) for AgClAgCl is 1.6×10−101.6 \times 10^{ - 10} at 298 K, what is the approximate value of \(\Delta G^\circ_{\text{dissolution}}\)?

    56.5 kJ/mol
  • If the KspK_{sp} for AgClAgCl is 1.6 \times 10^{ - 10}</latex> at 298 K, the ΔGdissolution∘\Delta G^\circ_{\text{dissolution}} is approximately 56.5 kJ/mol
  • How do you convert temperature from Celsius to Kelvin?
    T(K)=T (K) =T(°C)+ T (°C) +273.15 273.15
  • What does a ΔGdissolution\Delta G_{\text{dissolution}} of zero indicate about the system?

    At equilibrium
  • An increase in solute concentration makes dissolution less spontaneous.

    True
  • Increasing solute concentration decreases ΔGdissolution\Delta G_{\text{dissolution}} and makes dissolution less spontaneous.

    True
  • What does a negative value of ΔGdissolution\Delta G_{\text{dissolution}} indicate about the dissolution process?

    Spontaneous
  • What is the formula that relates \Delta G^\circ_{\text{dissolution}}</latex> to KspK_{sp}?

    ΔGdissolution∘=\Delta G^\circ_{\text{dissolution}} =−RTln⁡Ksp - RT \ln K_{sp}
  • What does a high value of KspK_{sp} indicate about the solubility of a substance?

    High solubility
  • The ideal gas constant RR is 8.314 J/mol·K.
  • When ΔGdissolution\Delta G_{\text{dissolution}} is zero, the system is at equilibrium.
  • Why does lead sulfate (PbSO_{4}</latex>) limit its spread in soil due to its ΔGdissolution\Delta G_{\text{dissolution}}?

    Positive ΔGdissolution\Delta G_{\text{dissolution}}
  • A negative \(\Delta G_{\text{dissolution}}\) indicates a spontaneous dissolution process.

    True
  • Match the condition of \(\Delta G_{\text{dissolution}}\) with the corresponding solubility:
    \(\Delta G_{\text{dissolution}} < 0\) ↔️ Spontaneous
    \(\Delta G_{\text{dissolution}} > 0\) ↔️ Non-spontaneous
    \(\Delta G_{\text{dissolution}} = 0\) ↔️ At equilibrium
  • The standard free energy change of dissolution (\(\Delta G^\circ_{\text{dissolution}}\)) is related to \(K_{sp}\) by the equation ΔGdissolution∘=\Delta G^\circ_{\text{dissolution}} =−RTln⁡Ksp - RT \ln K_{sp}.ln
  • What does the solubility product \(K_{sp}\) measure?
    Solubility of a solid
  • A higher \(K_{sp}\) results in a more negative \(\Delta G^\circ_{\text{dissolution}}\), making the dissolution process more spontaneous.
    True
  • A higher KspK_{sp} corresponds to a more negative ΔGdissolution∘\Delta G^\circ_{\text{dissolution}} and greater spontaneity.

    True
  • In the \Delta G = - RT\ln K_{sp}</latex> equation, RR is the ideal gas constant, which has a value of 8.314 J/mol·K
  • Match the \Delta G_{\text{dissolution}}</latex> condition with its corresponding solubility:
    ΔGdissolution<0\Delta G_{\text{dissolution}} < 0 ↔️ Spontaneous: Substance readily dissolves
    ΔGdissolution>0\Delta G_{\text{dissolution}} > 0 ↔️ Non-spontaneous: Substance does not readily dissolve
    ΔGdissolution=\Delta G_{\text{dissolution}} =0 0 ↔️ At equilibrium: System is at equilibrium
  • How does pressure affect ΔGdissolution\Delta G_{\text{dissolution}} for solids dissolving in liquids?

    Little effect
  • The free energy of dissolution (\(\Delta G_{\text{dissolution}}\)) is the change in Gibbs free energy
  • The equilibrium constant KspK_{sp} is also known as the solubility product.
  • The ideal gas constant RR has a value of 8.314 J/mol·K.
  • Steps to calculate free energy using \Delta G = - RT\ln K_{sp}</latex>
    1️⃣ Identify KspK_{sp}
    2️⃣ Convert temperature to Kelvin
    3️⃣ Calculate the natural logarithm of KspK_{sp}
    4️⃣ Multiply the result by −RT- RT
  • What does a negative value of ΔGdissolution\Delta G_{\text{dissolution}} indicate about the spontaneity of dissolution?

    Spontaneous
  • What is the formula that relates ΔGdissolution\Delta G_{\text{dissolution}} to enthalpy and entropy changes?

    ΔGdissolution=\Delta G_{\text{dissolution}} =ΔHdissolution−TΔSdissolution \Delta H_{\text{dissolution}} - T\Delta S_{\text{dissolution}}
  • A positive \(\Delta G_{\text{dissolution}}\) indicates a non-spontaneous dissolution process.non-spontaneous
  • When \(\Delta G_{\text{dissolution}}\) is positive, the substance will dissolve readily.
    False
  • What is the value of the ideal gas constant \(R\) in the equation?
    8.314 J/mol·K
  • A high \(K_{sp}\) indicates low solubility of the compound.
    False
  • What does a low KspK_{sp} indicate about the solubility of a substance?

    Low solubility
  • Steps to calculate free energy using \Delta G = - RT\ln K_{sp}</latex>
    1️⃣ Identify the KspK_{sp} value
    2️⃣ Convert temperature to Kelvin
    3️⃣ Calculate ln⁡Ksp\ln K_{sp}
    4️⃣ Multiply by −RT- RT
  • A negative ΔGdissolution\Delta G_{\text{dissolution}} indicates that the substance will readily dissolve.

    True
  • An increase in temperature generally decreases ΔGdissolution\Delta G_{\text{dissolution}}, making dissolution more spontaneous
  • The relationship between ΔGdissolution\Delta G_{\text{dissolution}}, enthalpy change ΔHdissolution\Delta H_{\text{dissolution}}, and entropy change ΔSdissolution\Delta S_{\text{dissolution}} is given by the equation: ΔGdissolution=\Delta G_{\text{dissolution}} =ΔHdissolution−TΔSdissolution \Delta H_{\text{dissolution}} - T\Delta S_{\text{dissolution}}entropy