Podcast
Questions and Answers
What does the second law of Thermodynamics state about spontaneous processes?
What does the second law of Thermodynamics state about spontaneous processes?
- The entropy of the Universe increases. (correct)
- The entropy of the Universe decreases.
- The entropy of isolated systems decreases.
- The entropy of the Universe remains constant.
How is the total entropy change of the Universe calculated?
How is the total entropy change of the Universe calculated?
- By multiplying the entropy changes of the system and surroundings.
- By averaging the entropy of the system and surroundings.
- By subtracting the entropy change of the system from that of the surroundings.
- By adding the entropy changes of the system and the surroundings. (correct)
What is the key requirement for evaluating the entropy change of a system?
What is the key requirement for evaluating the entropy change of a system?
- The process must be exothermic.
- Only reversible processes can be analyzed. (correct)
- The process must have a net entropy change of zero.
- The process must occur in a closed system.
In an isolated system, what is the possible condition for entropy change?
In an isolated system, what is the possible condition for entropy change?
What happens to the entropy of a system when a spontaneous process occurs in an isolated system?
What happens to the entropy of a system when a spontaneous process occurs in an isolated system?
What does the compressibility factor (Z) equal for ideal gases?
What does the compressibility factor (Z) equal for ideal gases?
What dominates at high pressures according to the behavior of real gases?
What dominates at high pressures according to the behavior of real gases?
What does the first law of thermodynamics state about energy in a closed system?
What does the first law of thermodynamics state about energy in a closed system?
Which of the following statements best describes work in the context of thermodynamics?
Which of the following statements best describes work in the context of thermodynamics?
How is heat defined in thermodynamics?
How is heat defined in thermodynamics?
What does internal energy (U) include?
What does internal energy (U) include?
Who received the Nobel Prize in Physics in 1910 for contributions to the understanding of gases?
Who received the Nobel Prize in Physics in 1910 for contributions to the understanding of gases?
What is the work done against the surrounding pressure referred to as?
What is the work done against the surrounding pressure referred to as?
What is the SI unit of heat capacity?
What is the SI unit of heat capacity?
How much heat is required to raise the temperature of 1 kg of water from 0 °C to 100 °C, given the specific heat is 4.19 kJ/kg·K?
How much heat is required to raise the temperature of 1 kg of water from 0 °C to 100 °C, given the specific heat is 4.19 kJ/kg·K?
Which term describes the heat capacity measured at constant volume?
Which term describes the heat capacity measured at constant volume?
What defines molar heat capacity?
What defines molar heat capacity?
Which of the following factors does not affect heat capacity in the case of ideal gases?
Which of the following factors does not affect heat capacity in the case of ideal gases?
What happens to the heat change in a system when the volume is constant during a process?
What happens to the heat change in a system when the volume is constant during a process?
In bomb calorimetry, what does the calorimeter primarily measure?
In bomb calorimetry, what does the calorimeter primarily measure?
Which statement is true regarding constant pressure processes?
Which statement is true regarding constant pressure processes?
What is the standard enthalpy change, ΔcH, for the combustion of glycine based on the provided calculations?
What is the standard enthalpy change, ΔcH, for the combustion of glycine based on the provided calculations?
In the combustion of methane, which functional relationship is used to find the change in enthalpy ΔcH?
In the combustion of methane, which functional relationship is used to find the change in enthalpy ΔcH?
Which statement correctly describes Hess’s Law?
Which statement correctly describes Hess’s Law?
What is the primary reason that pVm is negligible for liquids in calculations of enthalpy?
What is the primary reason that pVm is negligible for liquids in calculations of enthalpy?
During the combustion of methane, which of the following species experiences a change in enthalpy?
During the combustion of methane, which of the following species experiences a change in enthalpy?
Calculate the value of pVm for the liquid water under the given conditions.
Calculate the value of pVm for the liquid water under the given conditions.
What do the Δνgas values indicate in the context of enthalpy change calculations?
What do the Δνgas values indicate in the context of enthalpy change calculations?
In the provided chemical equation for the combustion of glycine, how many moles of O2 are required?
In the provided chemical equation for the combustion of glycine, how many moles of O2 are required?
What effect does adding heat have on an endothermic reaction?
What effect does adding heat have on an endothermic reaction?
According to the Van 't Hoff equation, what happens to the equilibrium constant K when temperature increases for an endothermic reaction?
According to the Van 't Hoff equation, what happens to the equilibrium constant K when temperature increases for an endothermic reaction?
Which of the following statements is true regarding exothermic reactions?
Which of the following statements is true regarding exothermic reactions?
What will happen to the concentration of hydrogen iodide when the temperature increases for the reaction H2(g) + I2(g) ⇄ 2HI(g)?
What will happen to the concentration of hydrogen iodide when the temperature increases for the reaction H2(g) + I2(g) ⇄ 2HI(g)?
What is indicated by a positive value of ΔH for a reaction?
What is indicated by a positive value of ΔH for a reaction?
In the reaction N2O4(g) ⇄ 2NO2(g), what effect does an increase in temperature have?
In the reaction N2O4(g) ⇄ 2NO2(g), what effect does an increase in temperature have?
If the ΔHo for CO(g) + H2O(g) ⇄ CO2(g) + H2(g) is -46 kJ, what type of reaction is this?
If the ΔHo for CO(g) + H2O(g) ⇄ CO2(g) + H2(g) is -46 kJ, what type of reaction is this?
In thermodynamics, what does a negative value of ΔG indicate?
In thermodynamics, what does a negative value of ΔG indicate?
What characterizes an open system in thermodynamics?
What characterizes an open system in thermodynamics?
Which property is an example of an extensive property?
Which property is an example of an extensive property?
How do state functions differ from path functions?
How do state functions differ from path functions?
Which of the following systems is correctly categorized as adiabatic?
Which of the following systems is correctly categorized as adiabatic?
What is the primary focus of thermodynamics?
What is the primary focus of thermodynamics?
Which pair of properties includes one extensive and one intensive property?
Which pair of properties includes one extensive and one intensive property?
What does it mean if a system is described as closed (diathermic)?
What does it mean if a system is described as closed (diathermic)?
Which of the following is a thermodynamic potential?
Which of the following is a thermodynamic potential?
What is the sign of the standard enthalpy change ΔcH for the combustion of glycine?
What is the sign of the standard enthalpy change ΔcH for the combustion of glycine?
What does the dimensionless number νgas represent in the context of enthalpy calculations?
What does the dimensionless number νgas represent in the context of enthalpy calculations?
What is represented by the activity 'a' of a substance in thermodynamics?
What is represented by the activity 'a' of a substance in thermodynamics?
In the combustion of methane, which component significantly contributes to the value of pVm in the enthalpy calculations?
In the combustion of methane, which component significantly contributes to the value of pVm in the enthalpy calculations?
What is the thermodynamic criterion for spontaneous change at constant temperature and pressure?
What is the thermodynamic criterion for spontaneous change at constant temperature and pressure?
According to Hess's Law, how is the change in enthalpy for a reaction determined?
According to Hess's Law, how is the change in enthalpy for a reaction determined?
According to the Law of Mass Action, what does the rate of a chemical reaction depend on?
According to the Law of Mass Action, what does the rate of a chemical reaction depend on?
Which of the following statements about the Gibbs energy of mixing is correct?
Which of the following statements about the Gibbs energy of mixing is correct?
What is the enthalpy change for the combustion of methane when specified conditions indicate ΔcH = -890 kJ?
What is the enthalpy change for the combustion of methane when specified conditions indicate ΔcH = -890 kJ?
How does the molar volume of gases compare to that of liquids, based on the discussed principles?
How does the molar volume of gases compare to that of liquids, based on the discussed principles?
At equilibrium, what can be expected about the amounts of reactants and products present?
At equilibrium, what can be expected about the amounts of reactants and products present?
In the provided example, what reaction enthalpy value reflects the overall change in the combustion of glycine?
In the provided example, what reaction enthalpy value reflects the overall change in the combustion of glycine?
What happens to the Gibbs energy when a reaction 'does not go' due to very little reactants being converted into products?
What happens to the Gibbs energy when a reaction 'does not go' due to very little reactants being converted into products?
How does the free energy of mixing for ideal gases relate to the component concentrations?
How does the free energy of mixing for ideal gases relate to the component concentrations?
What effect does the reaction pathway have on the calculated enthalpy change according to Hess’s Law?
What effect does the reaction pathway have on the calculated enthalpy change according to Hess’s Law?
Why is it necessary to consider non-ideal behavior in thermodynamic equations?
Why is it necessary to consider non-ideal behavior in thermodynamic equations?
What does a smaller value of the acidity constant, Ka, indicate about an acid?
What does a smaller value of the acidity constant, Ka, indicate about an acid?
Which of the following acids is considered a strong acid?
Which of the following acids is considered a strong acid?
What is the relationship between Ka and Kb regarding the strength of an acid and its conjugate base?
What is the relationship between Ka and Kb regarding the strength of an acid and its conjugate base?
For a weak base like ammonia (NH3), what can be said about its equilibrium constant Kb?
For a weak base like ammonia (NH3), what can be said about its equilibrium constant Kb?
Which of the following is true regarding the pH of a solution of a weak acid?
Which of the following is true regarding the pH of a solution of a weak acid?
How does pKa relate to the strength of an acid?
How does pKa relate to the strength of an acid?
What is the significance of the autoprotolysis constant for water, Kw?
What is the significance of the autoprotolysis constant for water, Kw?
What happens to the strength of a base as its conjugate acid's strength increases?
What happens to the strength of a base as its conjugate acid's strength increases?
What characterizes an endothermic reaction regarding heat?
What characterizes an endothermic reaction regarding heat?
What will happen if heat is removed from an endothermic reaction?
What will happen if heat is removed from an endothermic reaction?
According to the Van 't Hoff equation, how does an increase in temperature affect the equilibrium constant for an endothermic reaction?
According to the Van 't Hoff equation, how does an increase in temperature affect the equilibrium constant for an endothermic reaction?
In the reaction N2O4(g) ⇄ 2 NO2(g), what color change is observed when the temperature is increased?
In the reaction N2O4(g) ⇄ 2 NO2(g), what color change is observed when the temperature is increased?
What is the sign of ΔH for a reaction that favors low temperatures and is exothermic?
What is the sign of ΔH for a reaction that favors low temperatures and is exothermic?
In the reaction H2(g) + I2(g) ⇄ 2HI(g) with ΔH = -51.0 kJ, what will happen to the concentrations when temperature is increased?
In the reaction H2(g) + I2(g) ⇄ 2HI(g) with ΔH = -51.0 kJ, what will happen to the concentrations when temperature is increased?
What does a negative value of ΔG signify in a reaction?
What does a negative value of ΔG signify in a reaction?
For the reaction CO(g) + H2O(g) ⇄ CO2(g) + H2(g) with ΔH = -46 kJ, at high temperatures how is the equilibrium affected?
For the reaction CO(g) + H2O(g) ⇄ CO2(g) + H2(g) with ΔH = -46 kJ, at high temperatures how is the equilibrium affected?
What happens to the reaction rate when the pressure is increased by decreasing the volume of the container?
What happens to the reaction rate when the pressure is increased by decreasing the volume of the container?
In the reaction 2SO2(g) + O2(g) ⇄ 2SO3(g), which condition is favored if pressure is increased?
In the reaction 2SO2(g) + O2(g) ⇄ 2SO3(g), which condition is favored if pressure is increased?
What is the effect of reducing the volume of a container from 15 mL to 7.5 mL on the concentration of gases?
What is the effect of reducing the volume of a container from 15 mL to 7.5 mL on the concentration of gases?
For the reaction CO(g) + 2H2(g) ⇄ CH3OH(g), what is the expected behavior under increased pressure conditions?
For the reaction CO(g) + 2H2(g) ⇄ CH3OH(g), what is the expected behavior under increased pressure conditions?
According to Le Châtelier's Principle, what will happen to equilibrium when water is removed from an esterification reaction?
According to Le Châtelier's Principle, what will happen to equilibrium when water is removed from an esterification reaction?
How does temperature affect the equilibrium constant for an endothermic reaction?
How does temperature affect the equilibrium constant for an endothermic reaction?
What is the equilibrium position change when the forward reaction produces more moles of gas?
What is the equilibrium position change when the forward reaction produces more moles of gas?
What occurs at equilibrium between the forward and reverse reactions?
What occurs at equilibrium between the forward and reverse reactions?
What does the standard reaction enthalpy, Δ rH, represent?
What does the standard reaction enthalpy, Δ rH, represent?
In the context of predicting reaction enthalpy, what simplification is assumed regarding heat capacity?
In the context of predicting reaction enthalpy, what simplification is assumed regarding heat capacity?
What characterizes a reversible thermodynamic change?
What characterizes a reversible thermodynamic change?
How does the direction of spontaneous change in thermodynamic processes generally occur?
How does the direction of spontaneous change in thermodynamic processes generally occur?
When considering the enthalpy of reaction at different temperatures, which equation is relevant?
When considering the enthalpy of reaction at different temperatures, which equation is relevant?
Which scenario illustrates an irreversible process?
Which scenario illustrates an irreversible process?
What is the implication of equal internal and external pressures in a thermodynamic system?
What is the implication of equal internal and external pressures in a thermodynamic system?
Which factor is essential in determining whether reactions occur in a specific direction when considering thermodynamic laws?
Which factor is essential in determining whether reactions occur in a specific direction when considering thermodynamic laws?
Flashcards
System
System
The part of the universe we are investigating. It could be a block of iron, a beaker of water, an engine, or even a human body.
Surroundings
Surroundings
Everything beyond the system, including the air, walls, and even us observing the system
Boundaries
Boundaries
The boundary that defines what's inside the system and what's outside in the surroundings
Open System
Open System
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Closed System
Closed System
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Isolated System
Isolated System
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Extensive Property
Extensive Property
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Intensive Property
Intensive Property
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Compressibility Factor (Z)
Compressibility Factor (Z)
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Ideal Gas
Ideal Gas
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Van der Waals Equation
Van der Waals Equation
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Internal Energy (U)
Internal Energy (U)
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Work (w)
Work (w)
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Heat
Heat
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1st Law of Thermodynamics
1st Law of Thermodynamics
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Kinetic Gas Theory
Kinetic Gas Theory
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Molar heat capacity
Molar heat capacity
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Internal Energy Change at Constant Volume (ΔcU)
Internal Energy Change at Constant Volume (ΔcU)
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Enthalpy Change at Constant Pressure (ΔcH )
Enthalpy Change at Constant Pressure (ΔcH )
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Heat Capacity Equation
Heat Capacity Equation
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Heat Capacity
Heat Capacity
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Change in Number of Moles of Gas (Δνgas)
Change in Number of Moles of Gas (Δνgas)
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Isochore Heat Capacity (Cv)
Isochore Heat Capacity (Cv)
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Enthalpy of Combustion (ΔcH°)
Enthalpy of Combustion (ΔcH°)
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Hess's Law
Hess's Law
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Isobar Heat Capacity (Cp)
Isobar Heat Capacity (Cp)
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Constant Volume Processes (dU = dqV)
Constant Volume Processes (dU = dqV)
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State Function
State Function
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Combining Reaction Enthalpies Using Hess's Law
Combining Reaction Enthalpies Using Hess's Law
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Constant Pressure Processes
Constant Pressure Processes
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State Functions (U, P, V)
State Functions (U, P, V)
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Enthalpy Diagram
Enthalpy Diagram
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Second Law of Thermodynamics
Second Law of Thermodynamics
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Entropy Change of the Universe
Entropy Change of the Universe
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Entropy Change of the System
Entropy Change of the System
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Entropy as a State Function
Entropy as a State Function
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Entropy Change in an Isolated System
Entropy Change in an Isolated System
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Endothermic Reaction
Endothermic Reaction
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Van't Hoff Equation
Van't Hoff Equation
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Exothermic Reaction
Exothermic Reaction
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Chemical Equilibrium
Chemical Equilibrium
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Le Chatelier's Principle
Le Chatelier's Principle
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Catalyst
Catalyst
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Enthalpy Change (∆H)
Enthalpy Change (∆H)
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Gibbs Free Energy Change (∆G)
Gibbs Free Energy Change (∆G)
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Fuel and Food Properties
Fuel and Food Properties
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Standard Enthalpy of Formation (ΔHf°)
Standard Enthalpy of Formation (ΔHf°)
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Standard Reaction Enthalpy (ΔrH°)
Standard Reaction Enthalpy (ΔrH°)
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Kirchhoff's Equation
Kirchhoff's Equation
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Entropy (S)
Entropy (S)
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Activity (a)
Activity (a)
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Free Energy of Mixing (ΔGmix)
Free Energy of Mixing (ΔGmix)
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Law of Mass Action
Law of Mass Action
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K (Equilibrium Constant)
K (Equilibrium Constant)
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Pressure and Equilibrium
Pressure and Equilibrium
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Temperature and Equilibrium
Temperature and Equilibrium
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Acidity Constant (Ka)
Acidity Constant (Ka)
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Weak Acid
Weak Acid
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Strong Acid
Strong Acid
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Basicity Constant (Kb)
Basicity Constant (Kb)
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pKb
pKb
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Weak Base
Weak Base
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Strong Base
Strong Base
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Study Notes
Thermodynamics: Fundamentals
- Thermodynamics describes the macroscopic state of a complex system through a few macroscopic variables, such as pressure and temperature, known as state variables, and through thermodynamic potentials.
- This subject encompasses a wide range of phenomena, including the efficiency of heat engines and heat pumps, as well as chemical processes and life processes.
- Thermodynamics doesn't just focus on steam engines; it's about nearly everything.
Systems and Surroundings
- A system is the specific part of the universe being studied (e.g., a block of iron, a beaker of water, an engine, a human body).
- The surroundings refer to the rest of the universe outside the system.
- Systems are classified as open, closed, or isolated based on their interaction with the surroundings regarding matter and energy exchange.
Types of Systems
- Open system: Matter and energy can be exchanged between the system and its surroundings. (e.g., an open flask)
- Closed system (diathermic system): Only energy can be exchanged between the system and its surroundings. (e.g., a sealed bottle)
- Isolated system (adiabatic system): Neither matter nor energy can be exchanged with the surroundings. (e.g., a stoppered vacuum flask)
Properties of Systems
- Extensive properties: Depend on the amount of matter in the system (e.g., mass, volume). For example, 2kg of iron occupy twice the volume of 1 kg of iron.
- Intensive properties: Independent of the amount of matter in the system (e.g., temperature, density). For instance, the density of iron is 8.9 kg/cm³.
State and Path Functions
- State functions: Their value depends only on the current state of the system, not the path taken to reach that state (e.g., internal energy, enthalpy, entropy).
- Path functions: Their value depends on the path taken to reach the specific state (e.g., heat, work).
Laws of Thermodynamics
- Zeroth Law: All parts of a system in thermodynamic equilibrium have the same temperature. This is the basis of thermometers.
- First Law: Energy cannot be created or destroyed; it can only be transformed. The change in internal energy of a system is equal to the heat added to the system minus the work done by the system.
- Second Law: Spontaneous processes always proceed in the direction of increasing total entropy (in an isolated system). Reversible processes have zero change in entropy, while irreversible ones have a positive change.
- Third Law: The entropy of a perfect crystal approaches zero as the temperature approaches absolute zero.
Thermodynamic Temperature
- Thermodynamic temperature is measured in Kelvin (K).
- The Kelvin scale is equivalent to the Celsius scale.
Thermodynamic Processes
- Isochoric process: Constant volume (e.g., change in a sealed container)
- Isobaric process: Constant pressure (e.g., a reaction in an open container)
- Isothermal process: Constant temperature (e.g., a phase change)
- Adiabatic process: No heat exchange with the surroundings (e.g., a thermos).
Ideal Gas Law
- The state equation for an ideal gas is pV = nRT, where:
- p is pressure
- V is volume
- n is the number of moles
- R is the ideal gas constant
- T is temperature
Enthalpy (H)
- Enthalpy is a thermodynamic potential, defined as H = U + pV.
- It is used for constant-pressure processes because the enthalpy change, dH, is equal to the heat exchanged at constant pressure, qp.
- The relationship between enthalpy and temperature is dH = Cp dT
Standard Enthalpy of Formation
- The standard enthalpy of formation (ΔHf°) of a substance is the enthalpy change when one mole of the substance is formed from its constituent elements in their standard states at 298K and 1 atm of pressure.
Hess's Law
- Hess's law states that the enthalpy change of a reaction is independent of the pathway taken to reach the final state.
- The enthalpy change for a reaction can be determined by summing the enthalpy changes for any set of individual reaction steps that together achieve the original reaction.
Entropy (S)
- Entropy is a measure of disorder or randomness.
- The change in entropy (dS) for a process can be calculated as:
dS = dqrev / Tfor a reversible process
Gibbs Free Energy (G)
- Gibbs free energy (G) is a thermodynamic potential that measures the maximum reversible work that may be performed by a thermodynamically closed system at a constant temperature and pressure. It's defined as G = H - TS.
- A change in Gibbs free energy is related to the spontaneity of a process: If ∆G < 0, the process is spontaneous; ∆G = 0 corresponds to equilibrium; and ∆G > 0 corresponds to a non-spontaneous process.
Equilibrium Constant
- The equilibrium constant (K) relates the standard Gibbs energy change for a reaction (at a given temperature) to the equilibrium concentrations of the products and reactants: ∆G = −RT ln K
- The value of K indicates the relative amounts of products and reactants present at equilibrium, and it depends on temperature.
Le Châtelier's Principle
- When a change is made to a system in equilibrium, the system shifts in the direction that relieves the stress of the change
Reaction Rates
- Reaction rate is the speed at which a chemical reaction proceeds.
- The order of a reaction refers to the power of each reactant in the rate law.
Activation Energy
- Activation energy (Ea) is the minimum energy required for a reaction to occur
- The higher the Ea, the slower the rate of the reaction
Catalysts
- Catalysts increase the rate of a reaction by providing an alternative reaction pathways with lower activation energy, leading to higher reaction rates
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Description
Test your knowledge on the principles of thermodynamics with this comprehensive quiz. Covering topics such as the laws of thermodynamics, entropy changes, and properties of gases, it challenges your understanding of key concepts and equations. Perfect for students of physics or chemistry.
