AP Chemistry Flashcards: Free Energy Of Dissolution

Study Free Energy Of Dissolution in AP Chemistry with focused flashcards that help you recognize the idea, recall the key rule, and apply it in practice-style prompts.

AP Chemistry

Free Energy Of Dissolution

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QUESTION

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Calculate $\triangle G$ given $\triangle H = 10 \text{ kJ/mol}$ , $T = 298 \text{ K}$ , $\triangle S = 50 \text{ J/mol·K}$ .

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ANSWER

$\triangle G = -4.9 \text{ kJ/mol}$ . $\triangle G = 10000 - 298(50) = 10000 - 14900 = -4900$ J/mol.

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This deck focuses on Free Energy Of Dissolution, giving you a quick way to review the definitions, rules, and examples that matter most for AP Chemistry.

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Flashcard 1: Calculate $\triangle G$ given $\triangle H = 10 \text{ kJ/mol}$ , $T = 298 \text{ K}$ , $\triangle S = 50 \text{ J/mol·K}$ .

Answer: $\triangle G = -4.9 \text{ kJ/mol}$ . $\triangle G = 10000 - 298(50) = 10000 - 14900 = -4900$ J/mol.

Flashcard 2: Which quantity becomes zero at the dissolution equilibrium point?

Answer: $\triangle G$ . Free energy equals zero when forward and reverse rates are equal.

Flashcard 3: What is the sign of $\triangle G$ when $\triangle H < 0$ and $\triangle S > 0$ ?

Answer: $\triangle G < 0$ . Both terms favor spontaneity, making $\triangle G$ always negative.

Flashcard 4: What is the primary driver of dissolution for ionic solids in water?

Answer: Entropy increase. Breaking crystal lattice increases disorder despite ion-water interactions.

Flashcard 5: Calculate $\triangle G$ with $\triangle H = 20 \text{ kJ/mol}$ , $T = 350 \text{ K}$ , $\triangle S = 70 \text{ J/mol·K}$ .

Answer: $\triangle G = -4.5 \text{ kJ/mol}$ . $\triangle G = 20000 - 350(70) = 20000 - 24500 = -4500$ J/mol.

Flashcard 6: Which parameter is zero for a process at equilibrium?

Answer: $\triangle G$ . At equilibrium, the free energy change equals zero.

Flashcard 7: Determine the spontaneity: $\triangle H = 5 \text{ kJ/mol}$ , $T = 298 \text{ K}$ , $\triangle S = 30 \text{ J/mol·K}$ .

Answer: Spontaneous. $\triangle G = 5000 - 298(30) = 5000 - 8940 = -3940$ J/mol, so spontaneous.

Flashcard 8: What is the sign of $\triangle H$ if dissolution absorbs heat?

Answer: $\triangle H > 0$ . Positive enthalpy indicates an endothermic heat-absorbing process.

Flashcard 9: What does a positive $\triangle S$ indicate about entropy in dissolution?

Answer: Entropy increases. Positive $\triangle S$ means the system becomes more disordered.

Flashcard 10: What is indicated by a positive $\triangle G$ in dissolution?

Answer: Non-spontaneous process. Positive free energy means the process is thermodynamically unfavorable.

Flashcard 11: What determines the spontaneity of a dissolution process?

Answer: Sign of $\triangle G$ . Negative $\triangle G$ means spontaneous, positive means non-spontaneous.

Flashcard 12: Determine the spontaneity: $\Delta H = 5 \text{ kJ/mol}$ , $T = 298 \text{ K}$ , $\Delta S = 30 \text{ J/mol·K}$ .

Answer: Spontaneous. $\Delta G = 5000 - 298(30) = 5000 - 8940 = -3940$ J/mol, so spontaneous.

Flashcard 13: What is the sign of $\triangle G$ when $\triangle H < 0$ and $\triangle S > 0$ ?

Answer: $\triangle G < 0$ . Both terms favor spontaneity, making $\triangle G$ always negative.

Flashcard 14: Calculate $\triangle G$ when $\triangle H = 15 \text{ kJ/mol}$ , $T = 300 \text{ K}$ , $\triangle S = 60 \text{ J/mol·K}$ .

Answer: $\triangle G = -3 \text{ kJ/mol}$ . $\triangle G = 15000 - 300(60) = 15000 - 18000 = -3000$ J/mol.

Flashcard 15: What does a positive $\triangle S$ indicate about entropy in dissolution?

Answer: Entropy increases. Positive $\triangle S$ means the system becomes more disordered.

Flashcard 16: Determine the spontaneity: $\triangle H = 5 \text{ kJ/mol}$ , $T = 298 \text{ K}$ , $\triangle S = 30 \text{ J/mol·K}$ .

Answer: Spontaneous. $\triangle G = 5000 - 298(30) = 5000 - 8940 = -3940$ J/mol, so spontaneous.

Flashcard 17: State the condition for a dissolution to be spontaneous at all temperatures.

Answer: $\triangle H < 0$ , $\triangle S > 0$ . Exothermic enthalpy and positive entropy ensure spontaneity.

Flashcard 18: What is the sign of $\triangle G$ when dissolution is at equilibrium?

Answer: $\triangle G = 0$ . Zero free energy indicates the system has reached equilibrium.

Flashcard 19: Find the entropy change: $\triangle G = 10 \text{ kJ/mol}$ , $\triangle H = 15 \text{ kJ/mol}$ , $T = 298 \text{ K}$ .

Answer: $\triangle S = 16.78 \text{ J/mol·K}$ . $\triangle S = (\triangle H - \triangle G)/T = (15000 - 10000)/298 = 16.78$ J/mol·K.

Flashcard 20: What does a positive $\triangle S$ indicate about entropy in dissolution?

Answer: Entropy increases. Positive $\triangle S$ means the system becomes more disordered.

Flashcard 21: What is the relationship between $\triangle H$ and $\triangle S$ in spontaneous dissolution?

Answer: $\triangle H < T\triangle S$ . For spontaneity, the entropy term must overcome unfavorable enthalpy.

Flashcard 22: What is the unit of Gibbs free energy change?

Answer: Joules (J) or kilojoules (kJ). Energy units for thermodynamic quantities in the SI system.

Flashcard 23: State the effect on $\triangle G$ if both $\triangle H$ and $\triangle S$ are positive.

Answer: Depends on $T$ . Sign depends on whether $T\triangle S$ is greater or less than $\triangle H$ .

Flashcard 24: Which factor affects the sign of $\triangle G$ at constant pressure and temperature?

Answer: Enthalpy and entropy. Both enthalpy and entropy contributions determine free energy sign.

Flashcard 25: What effect does increased pressure have on gas solubility in liquids?

Answer: Increases solubility. Henry's law: gas solubility is directly proportional to pressure.

Flashcard 26: Identify the factor that primarily affects $\triangle S$ in dissolution.

Answer: Molecular disorder. Dissolution typically increases randomness as molecules spread out.

Flashcard 27: What does a negative $\triangle S$ for dissolution indicate?

Answer: Entropy decreases. Negative entropy change indicates decreased molecular disorder.

Flashcard 28: What is the formula for Gibbs free energy change?

Answer: $\triangle G = \triangle H - T\triangle S$ . Fundamental thermodynamic equation relating free energy to enthalpy and entropy.

Flashcard 29: Identify the formula for entropy change.

Answer: $\triangle S = \frac{\triangle H - \triangle G}{T}$ . Rearranged form of the Gibbs free energy equation.

Flashcard 30: What does a positive $\triangle S$ indicate about entropy in dissolution?

Answer: Entropy increases. Positive $\triangle S$ means the system becomes more disordered.

Flashcard 31: Identify the term for the heat change during dissolution.

Answer: Enthalpy change ( $\triangle H$ ). Enthalpy measures the heat absorbed or released during the process.

Flashcard 32: Identify the factor that primarily affects $\triangle S$ in dissolution.

Answer: Molecular disorder. Dissolution typically increases randomness as molecules spread out.

Flashcard 33: Which parameter is affected by both enthalpy and entropy in dissolution?

Answer: Gibbs free energy ( $\triangle G$ ). Free energy depends on both $\triangle H$ and $T\triangle S$ terms.

Flashcard 34: Calculate $\triangle H$ given $\triangle G = -3 \text{ kJ/mol}$ , $T = 310 \text{ K}$ , $\triangle S = 80 \text{ J/mol·K}$ .

Answer: $\triangle H = 21.8 \text{ kJ/mol}$ . $\triangle H = \triangle G + T\triangle S = -3000 + 310(80) = 21800$ J/mol.

Flashcard 35: What type of process occurs when $\triangle G > 0$ ?

Answer: Non-spontaneous process. Positive free energy indicates thermodynamically unfavorable conditions.

Flashcard 36: What is the significance of $\triangle G = 0$ in dissolution?

Answer: Equilibrium state. Zero free energy indicates the system is at thermodynamic equilibrium.

Flashcard 37: Calculate the enthalpy change: $\Delta G = -5 \text{ kJ/mol}$ , $T = 298 \text{ K}$ , $\Delta S = 20 \text{ J/mol·K}$ .

Answer: $\Delta H = 1.96 \text{ kJ/mol}$ . $\Delta H = \Delta G + T \Delta S = -5000 + 298(20) = 1960$ J/mol.

Flashcard 38: Determine the spontaneity: $\triangle H = 5 \text{ kJ/mol}$ , $T = 298 \text{ K}$ , $\triangle S = 30 \text{ J/mol·K}$ .

Answer: Spontaneous. $\triangle G = 5000 - 298(30) = 5000 - 8940 = -3940$ J/mol, so spontaneous.

Flashcard 39: What is the effect of increasing temperature on an exothermic dissolution?

Answer: Decreases solubility. Le Chatelier's principle: heat addition shifts equilibrium away from products.

Flashcard 40: Which variable increases the dissolution rate in endothermic reactions?

Answer: Temperature. Higher kinetic energy from temperature increases dissolution rate.

Flashcard 41: How does the dissolution of a gas in a liquid typically affect $\Delta S$ ?

Answer: $\Delta S$ decreases. Gas molecules become more ordered when dissolved in liquid.

Flashcard 42: What is the formula for Gibbs free energy change?

Answer: $\triangle G = \triangle H - T\triangle S$ . Fundamental thermodynamic equation relating free energy to enthalpy and entropy.

Flashcard 43: In dissolution, what does a negative $\triangle H$ imply?

Answer: Exothermic process. Negative enthalpy means heat is released to the surroundings.

Flashcard 44: State the sign of $\triangle G$ for a spontaneous dissolution.

Answer: $\triangle G < 0$ . Negative free energy indicates a thermodynamically favorable process.

Flashcard 45: Identify the type of dissolution with $\triangle S > 0$ and $\triangle H < 0$ .

Answer: Spontaneous dissolution. Both favorable enthalpy and entropy make $\triangle G$ negative at all temperatures.

Flashcard 46: Identify the term for the heat change during dissolution.

Answer: Enthalpy change ( $\triangle H$ ). Enthalpy measures the heat absorbed or released during the process.

AP Chemistry Flashcards: Free Energy Of Dissolution

Free Energy Of Dissolution

What this deck covers

How to use these flashcards

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Flashcard 1: Calculate △G\triangle G△G given △H=10 kJ/mol\triangle H = 10 \text{ kJ/mol}△H=10 kJ/mol, T=298 KT = 298 \text{ K}T=298 K, △S=50 J/mol\cdotpK\triangle S = 50 \text{ J/mol·K}△S=50 J/mol\cdotpK.

Flashcard 2: Which quantity becomes zero at the dissolution equilibrium point?

Flashcard 3: What is the sign of △G\triangle G△G when △H<0\triangle H < 0△H<0 and △S>0\triangle S > 0△S>0?

Flashcard 4: What is the primary driver of dissolution for ionic solids in water?

Flashcard 5: Calculate △G\triangle G△G with △H=20 kJ/mol\triangle H = 20 \text{ kJ/mol}△H=20 kJ/mol, T=350 KT = 350 \text{ K}T=350 K, △S=70 J/mol\cdotpK\triangle S = 70 \text{ J/mol·K}△S=70 J/mol\cdotpK.

Flashcard 6: Which parameter is zero for a process at equilibrium?

Flashcard 7: Determine the spontaneity: △H=5 kJ/mol\triangle H = 5 \text{ kJ/mol}△H=5 kJ/mol, T=298 KT = 298 \text{ K}T=298 K, △S=30 J/mol\cdotpK\triangle S = 30 \text{ J/mol·K}△S=30 J/mol\cdotpK.

Flashcard 8: What is the sign of △H\triangle H△H if dissolution absorbs heat?

Flashcard 9: What does a positive △S\triangle S△S indicate about entropy in dissolution?

Flashcard 10: What is indicated by a positive △G\triangle G△G in dissolution?

Flashcard 11: What determines the spontaneity of a dissolution process?

Flashcard 12: Determine the spontaneity: ΔH=5 kJ/mol\Delta H = 5 \text{ kJ/mol}ΔH=5 kJ/mol, T=298 KT = 298 \text{ K}T=298 K, ΔS=30 J/mol\cdotpK\Delta S = 30 \text{ J/mol·K}ΔS=30 J/mol\cdotpK.

Flashcard 13: What is the sign of △G\triangle G△G when △H<0\triangle H < 0△H<0 and △S>0\triangle S > 0△S>0?

Flashcard 14: Calculate △G\triangle G△G when △H=15 kJ/mol\triangle H = 15 \text{ kJ/mol}△H=15 kJ/mol, T=300 KT = 300 \text{ K}T=300 K, △S=60 J/mol\cdotpK\triangle S = 60 \text{ J/mol·K}△S=60 J/mol\cdotpK.

Flashcard 15: What does a positive △S\triangle S△S indicate about entropy in dissolution?

Flashcard 16: Determine the spontaneity: △H=5 kJ/mol\triangle H = 5 \text{ kJ/mol}△H=5 kJ/mol, T=298 KT = 298 \text{ K}T=298 K, △S=30 J/mol\cdotpK\triangle S = 30 \text{ J/mol·K}△S=30 J/mol\cdotpK.

Flashcard 17: State the condition for a dissolution to be spontaneous at all temperatures.

Flashcard 18: What is the sign of △G\triangle G△G when dissolution is at equilibrium?

Flashcard 19: Find the entropy change: △G=10 kJ/mol\triangle G = 10 \text{ kJ/mol}△G=10 kJ/mol, △H=15 kJ/mol\triangle H = 15 \text{ kJ/mol}△H=15 kJ/mol, T=298 KT = 298 \text{ K}T=298 K.

Flashcard 20: What does a positive △S\triangle S△S indicate about entropy in dissolution?

Flashcard 21: What is the relationship between △H\triangle H△H and △S\triangle S△S in spontaneous dissolution?

Flashcard 22: What is the unit of Gibbs free energy change?

Flashcard 23: State the effect on △G\triangle G△G if both △H\triangle H△H and △S\triangle S△S are positive.

Flashcard 24: Which factor affects the sign of △G\triangle G△G at constant pressure and temperature?

Flashcard 25: What effect does increased pressure have on gas solubility in liquids?

Flashcard 26: Identify the factor that primarily affects △S\triangle S△S in dissolution.

Flashcard 27: What does a negative △S\triangle S△S for dissolution indicate?

Flashcard 28: What is the formula for Gibbs free energy change?

Flashcard 29: Identify the formula for entropy change.

Flashcard 30: What does a positive △S\triangle S△S indicate about entropy in dissolution?

Flashcard 31: Identify the term for the heat change during dissolution.

Flashcard 32: Identify the factor that primarily affects △S\triangle S△S in dissolution.

Flashcard 33: Which parameter is affected by both enthalpy and entropy in dissolution?

Flashcard 34: Calculate △H\triangle H△H given △G=−3 kJ/mol\triangle G = -3 \text{ kJ/mol}△G=−3 kJ/mol, T=310 KT = 310 \text{ K}T=310 K, △S=80 J/mol\cdotpK\triangle S = 80 \text{ J/mol·K}△S=80 J/mol\cdotpK.

Flashcard 35: What type of process occurs when △G>0\triangle G > 0△G>0?

Flashcard 36: What is the significance of △G=0\triangle G = 0△G=0 in dissolution?

Flashcard 37: Calculate the enthalpy change: ΔG=−5 kJ/mol\Delta G = -5 \text{ kJ/mol}ΔG=−5 kJ/mol, T=298 KT = 298 \text{ K}T=298 K, ΔS=20 J/mol\cdotpK\Delta S = 20 \text{ J/mol·K}ΔS=20 J/mol\cdotpK.

Flashcard 38: Determine the spontaneity: △H=5 kJ/mol\triangle H = 5 \text{ kJ/mol}△H=5 kJ/mol, T=298 KT = 298 \text{ K}T=298 K, △S=30 J/mol\cdotpK\triangle S = 30 \text{ J/mol·K}△S=30 J/mol\cdotpK.

Flashcard 39: What is the effect of increasing temperature on an exothermic dissolution?

Flashcard 40: Which variable increases the dissolution rate in endothermic reactions?

Flashcard 41: How does the dissolution of a gas in a liquid typically affect ΔS\Delta SΔS?

Flashcard 42: What is the formula for Gibbs free energy change?

Flashcard 43: In dissolution, what does a negative △H\triangle H△H imply?

Flashcard 44: State the sign of △G\triangle G△G for a spontaneous dissolution.

Flashcard 45: Identify the type of dissolution with △S>0\triangle S > 0△S>0 and △H<0\triangle H < 0△H<0.

Flashcard 46: Identify the term for the heat change during dissolution.

Flashcard 1: Calculate $\triangle G$ given $\triangle H = 10 \text{ kJ/mol}$ , $T = 298 \text{ K}$ , $\triangle S = 50 \text{ J/mol·K}$ .

Flashcard 3: What is the sign of $\triangle G$ when $\triangle H < 0$ and $\triangle S > 0$ ?

Flashcard 5: Calculate $\triangle G$ with $\triangle H = 20 \text{ kJ/mol}$ , $T = 350 \text{ K}$ , $\triangle S = 70 \text{ J/mol·K}$ .

Flashcard 7: Determine the spontaneity: $\triangle H = 5 \text{ kJ/mol}$ , $T = 298 \text{ K}$ , $\triangle S = 30 \text{ J/mol·K}$ .

Flashcard 8: What is the sign of $\triangle H$ if dissolution absorbs heat?

Flashcard 9: What does a positive $\triangle S$ indicate about entropy in dissolution?

Flashcard 10: What is indicated by a positive $\triangle G$ in dissolution?

Flashcard 12: Determine the spontaneity: $\Delta H = 5 \text{ kJ/mol}$ , $T = 298 \text{ K}$ , $\Delta S = 30 \text{ J/mol·K}$ .

Flashcard 13: What is the sign of $\triangle G$ when $\triangle H < 0$ and $\triangle S > 0$ ?

Flashcard 14: Calculate $\triangle G$ when $\triangle H = 15 \text{ kJ/mol}$ , $T = 300 \text{ K}$ , $\triangle S = 60 \text{ J/mol·K}$ .

Flashcard 15: What does a positive $\triangle S$ indicate about entropy in dissolution?

Flashcard 16: Determine the spontaneity: $\triangle H = 5 \text{ kJ/mol}$ , $T = 298 \text{ K}$ , $\triangle S = 30 \text{ J/mol·K}$ .

Flashcard 18: What is the sign of $\triangle G$ when dissolution is at equilibrium?

Flashcard 19: Find the entropy change: $\triangle G = 10 \text{ kJ/mol}$ , $\triangle H = 15 \text{ kJ/mol}$ , $T = 298 \text{ K}$ .

Flashcard 20: What does a positive $\triangle S$ indicate about entropy in dissolution?

Flashcard 21: What is the relationship between $\triangle H$ and $\triangle S$ in spontaneous dissolution?

Flashcard 23: State the effect on $\triangle G$ if both $\triangle H$ and $\triangle S$ are positive.

Flashcard 24: Which factor affects the sign of $\triangle G$ at constant pressure and temperature?

Flashcard 26: Identify the factor that primarily affects $\triangle S$ in dissolution.

Flashcard 27: What does a negative $\triangle S$ for dissolution indicate?

Flashcard 30: What does a positive $\triangle S$ indicate about entropy in dissolution?

Flashcard 32: Identify the factor that primarily affects $\triangle S$ in dissolution.

Flashcard 34: Calculate $\triangle H$ given $\triangle G = -3 \text{ kJ/mol}$ , $T = 310 \text{ K}$ , $\triangle S = 80 \text{ J/mol·K}$ .

Flashcard 35: What type of process occurs when $\triangle G > 0$ ?

Flashcard 36: What is the significance of $\triangle G = 0$ in dissolution?

Flashcard 37: Calculate the enthalpy change: $\Delta G = -5 \text{ kJ/mol}$ , $T = 298 \text{ K}$ , $\Delta S = 20 \text{ J/mol·K}$ .

Flashcard 38: Determine the spontaneity: $\triangle H = 5 \text{ kJ/mol}$ , $T = 298 \text{ K}$ , $\triangle S = 30 \text{ J/mol·K}$ .

Flashcard 41: How does the dissolution of a gas in a liquid typically affect $\Delta S$ ?

Flashcard 43: In dissolution, what does a negative $\triangle H$ imply?

Flashcard 44: State the sign of $\triangle G$ for a spontaneous dissolution.

Flashcard 45: Identify the type of dissolution with $\triangle S > 0$ and $\triangle H < 0$ .