Thermodynamics and Kinetics Overview

Questions and Answers

What does a negative Gibbs free energy (delta G) indicate about a reaction?

The reaction requires energy input.

The reaction is spontaneous. (correct)

The reaction is at equilibrium.

The reaction is endergonic.

A reaction with a positive delta G is described as exergonic.

False

What is the Gibbs free energy when a reaction reaches equilibrium?

zero

A reaction that is non-spontaneous requires an input of __________.

energy Signup and view all the answers

Match the following terms with their definitions:

Spontaneous Reaction = Reaction that proceeds without external energy Endergonic = Reaction that requires energy input Equilibrium = State when delta G equals zero Exergonic = Reaction that releases energy Signup and view all the answers

Which term is synonymous with a spontaneous reaction?

Exergonic Signup and view all the answers

An exergonic reaction is one that absorbs energy.

False Signup and view all the answers

What happens to the value of delta G as a reaction approaches equilibrium?

It approaches zero. Signup and view all the answers

A reaction with delta G greater than zero is considered __________.

non-spontaneous Signup and view all the answers

Match the conditions with their corresponding delta G implications:

Delta G < 0 = Spontaneous reaction Delta G > 0 = Non-spontaneous reaction Delta G = 0 = Equilibrium Endergonic = Delta G > 0 Signup and view all the answers

What does a large equilibrium constant (K) indicate about a reaction?

The reaction strongly favors the products. Signup and view all the answers

Delta G can be used to indicate whether a reaction is spontaneous or non-spontaneous.

True Signup and view all the answers

What does the symbol 'ΔG°' represent?

Standard Gibbs free energy change Signup and view all the answers

Under standard conditions, concentrations of reactants and products are __________ molar.

one Signup and view all the answers

Match the equilibrium constants with their implications:

K >> 1 = Favors products K << 1 = Favors reactants K ≈ 1 = No strong preference Signup and view all the answers

At what temperature are standard conditions most commonly considered?

25 degrees Celsius Signup and view all the answers

A very small equilibrium constant implies many products at equilibrium.

False Signup and view all the answers

What are the units for the standard Gibbs free energy change (ΔG°)?

Joules per mole Signup and view all the answers

Standard conditions often imply a temperature of __________ Kelvin.

298 Signup and view all the answers

If the value of K is 0.001, what does it indicate?

There are more reactants than products. Signup and view all the answers

What is the effect of a negative delta G standard on the equilibrium constant K?

K is greater than 1 Signup and view all the answers

A catalyst is consumed in the overall balanced chemical reaction.

False Signup and view all the answers

What do we call the energy barrier that must be overcome for a reaction to proceed?

activation energy Signup and view all the answers

At equilibrium, if delta G standard is equal to 0, the equilibrium constant K is equal to _____

1 Signup and view all the answers

Match the delta G standards with their corresponding equilibrium constants:

Negative = K is greater than 1 Zero = K is equal to 1 Positive = K is less than 1 Signup and view all the answers

Which statement accurately describes the function of a catalyst?

It provides an alternate pathway with lower activation energy. Signup and view all the answers

A catalyst can speed up the reaction in only the forward direction.

False Signup and view all the answers

What are biological catalysts in living organisms called?

enzymes Signup and view all the answers

A catalyst lowers the activation energy and allows a reaction to proceed _____ than it would without the catalyst.

faster Signup and view all the answers

Match the following terms with their definitions:

Delta G = Change in Gibbs free energy Equilibrium Constant K = A measure of the ratio of products to reactants at equilibrium Activation Energy = Energy required to start a reaction Signup and view all the answers

What does a negative delta G standard indicate about a reaction?

The reaction favors the products at equilibrium. Signup and view all the answers

If the equilibrium constant K is less than 1, it means the forward reaction is spontaneous.

False Signup and view all the answers

According to the relationship between delta G standard and the equilibrium constant, what can be concluded if delta G standard is positive?

The reverse reaction is spontaneous. Signup and view all the answers

In thermodynamics, under standard conditions, a delta G standard that is negative suggests that the equilibrium constant K is __________.

greater than 1 Signup and view all the answers

Match the delta G standard values with their implications on reaction spontaneity:

Delta G standard < 0 = Forward reaction is spontaneous Delta G standard > 0 = Reverse reaction is spontaneous Delta G standard = 0 = System is at equilibrium Equilibrium constant K > 1 = Favors products at equilibrium Signup and view all the answers

What is the relationship between delta G standard and the natural logarithm of the equilibrium constant K?

Delta G standard equals negative RTL and K. Signup and view all the answers

A reaction with a delta G standard of zero is considered to be spontaneous.

False Signup and view all the answers

What happens to the equilibrium constant K when delta G standard is negative?

K becomes greater than 1. Signup and view all the answers

If more reactants are present compared to products at equilibrium, then delta G standard is likely __________.

positive Signup and view all the answers

Which of the following correctly describes the significance of the equilibrium constant K?

K represents the ratio of products to reactants at equilibrium. Signup and view all the answers

What does a large equilibrium constant (K) indicate about a reaction?

More products than reactants at equilibrium Signup and view all the answers

Under standard conditions, all reactant concentrations are one molar.

True Signup and view all the answers

What is the temperature commonly associated with standard conditions in Celsius?

25 Signup and view all the answers

When the equilibrium constant K is much greater than 1, the reaction favors the ______.

products Signup and view all the answers

Match the following equilibrium constants with their implications:

K > 1000 = Favors products K ≈ 1 = Neither products nor reactants are favored K < 0.001 = Favors reactants K = 0 = No reaction occurs Signup and view all the answers

What does a very small equilibrium constant suggest about a reaction?

Higher concentration of reactants than products Signup and view all the answers

Concentrations can be negative in equilibrium calculations.

False Signup and view all the answers

What does the symbol 'ΔG°' represent?

Standard Gibbs free energy change Signup and view all the answers

Under standard conditions, gases are measured at a partial pressure of ______ atmosphere.

one Signup and view all the answers

Match the following delta G types with their corresponding reaction implications:

ΔG < 0 = Spontaneous reaction ΔG = 0 = Equilibrium ΔG > 0 = Non-spontaneous reaction ΔG and K are not directly related = Incorrect implication Signup and view all the answers

What happens to free energy when a spontaneous reaction occurs?

It decreases Signup and view all the answers

A positive delta G indicates that a reaction is spontaneous.

False Signup and view all the answers

What term is used to describe reactions that are spontaneous?

Exergonic Signup and view all the answers

When a reaction reaches equilibrium, delta G is equal to __________.

zero Signup and view all the answers

Match the terms related to Gibbs free energy with their meanings:

Exergonic = Reaction with negative delta G Endergonic = Reaction with positive delta G Spontaneous = Reaction that occurs without external energy Equilibrium = State where delta G equals zero Signup and view all the answers

Which of the following conditions indicates that a reaction needs energy from its surroundings?

Delta G is positive Signup and view all the answers

At equilibrium, the value of delta G becomes a large negative number.

False Signup and view all the answers

What does a reaction with a negative delta G imply about its direction?

It proceeds spontaneously in the forward direction. Signup and view all the answers

A reaction requiring an input of energy is described as __________.

endergonic Signup and view all the answers

Match the Gibbs free energy terms with their descriptions:

Delta G < 0 = Spontaneous reaction Delta G > 0 = Non-spontaneous reaction Delta G = 0 = Equilibrium state Spontaneous = Exergonic reaction Signup and view all the answers

What does a negative delta G standard indicate about the direction of a reaction?

The reaction is spontaneous under standard conditions. Signup and view all the answers

If delta G standard is positive, then the reaction favors the products at equilibrium.

False Signup and view all the answers

What is the relationship between delta G standard and the equilibrium constant K if delta G standard is negative?

K is greater than 1 Signup and view all the answers

If the natural log of K is positive, then delta G standard is __________.

negative Signup and view all the answers

Match the following delta G standard values with their implications:

Negative = The reaction is spontaneous. Positive = The reaction is non-spontaneous. Zero = The reaction is at equilibrium. Signup and view all the answers

What is the primary implication of having an equilibrium constant K less than 1?

The reaction favors reactants. Signup and view all the answers

An equilibrium constant K of 1 indicates that the reactants and products are present in equal concentrations at equilibrium.

True Signup and view all the answers

What does a larger equilibrium constant indicate about a reaction?

It favors the formation of products. Signup and view all the answers

The equation relating delta G standard to the equilibrium constant is delta G standard = __________.

−RTLn(K) Signup and view all the answers

What will happen to delta G standard if the forward reaction becomes spontaneous?

It will become negative. Signup and view all the answers

What effect does a catalyst have on the activation energy of a reaction?

Decreases the activation energy Signup and view all the answers

A catalyst is consumed in the overall balanced chemical reaction.

False Signup and view all the answers

What is the role of a catalyst in a chemical reaction?

To speed up the reaction by lowering the activation energy. Signup and view all the answers

Enzymes are biological __________ that speed up reactions in living organisms.

catalysts Signup and view all the answers

Match the following terms with their correct definitions:

Catalyst = Speeds up both forward and reverse reactions Activation Energy = Energy barrier for a reaction Transition State = The peak of the energy barrier Equilibrium Constant (K) = Ratio of products to reactants at equilibrium Signup and view all the answers

When delta G standard is 0, what is the value of the equilibrium constant (K)?

Equal to 1 Signup and view all the answers

A catalyst speeds up the reaction only in the forward direction.

False Signup and view all the answers

What condition is generally required for delta G standard to indicate a spontaneous reaction?

Delta G standard must be negative. Signup and view all the answers

The energy barrier that must be overcome for a reaction to proceed is called the __________.

activation energy Signup and view all the answers

What is a common characteristic of a reaction with a positive delta G standard?

Reactants are favored at equilibrium Signup and view all the answers

Study Notes

Thermodynamics and Kinetics Overview

Gibbs free energy (ΔG) determines spontaneity of reactions; negative ΔG indicates spontaneous reactions, known as exergonic.
Exergonic reactions proceed downhill in free energy; they release energy to do work.
Non-spontaneous reactions (positive ΔG) are referred to as endergonic, requiring energy input from surroundings to proceed.
Reactions proceed spontaneously until equilibrium is reached, indicated by ΔG equaling zero.

Gibbs Free Energy and Equilibrium

Standard conditions for ΔG: all reactant concentrations at 1 M, gases at 1 atm, and typically 25°C (298 K).
The equilibrium constant (K) represents the concentration ratio of products to reactants at equilibrium.
A large K (greater than 1, especially above 1000) indicates a reaction that favors products.
A small K (less than 1) shows a reaction that favors reactants; K cannot be negative as concentrations are non-negative.
K around 1 suggests a balanced reaction with significant amounts of both products and reactants.

Relationship Between ΔG and K

The equation ΔG° = -RT ln K relates standard Gibbs free energy to the equilibrium constant.
Negative ΔG° indicates a spontaneous reaction under standard conditions, resulting in K > 1 (favoring products).
Positive ΔG° signifies a non-spontaneous reaction, leading to K < 1 (favoring reactants).
When ΔG° = 0, the equilibrium constant K equals 1, which is a rare occurrence.

Catalysts and Enzymes

Catalysts speed up reactions by providing an alternative pathway with lower activation energy.
Lower activation energy allows reactions to proceed more quickly, affecting both forward and reverse directions.
Catalysts are not consumed in the overall reaction and can facilitate multiple reactions without being depleted.
Enzymes function as biological catalysts, repeating the process for successive reactions in living organisms.

Thermodynamics and Kinetics Overview

Gibbs free energy (ΔG) determines spontaneity of reactions; negative ΔG indicates spontaneous reactions, known as exergonic.
Exergonic reactions proceed downhill in free energy; they release energy to do work.
Non-spontaneous reactions (positive ΔG) are referred to as endergonic, requiring energy input from surroundings to proceed.
Reactions proceed spontaneously until equilibrium is reached, indicated by ΔG equaling zero.

Gibbs Free Energy and Equilibrium

Standard conditions for ΔG: all reactant concentrations at 1 M, gases at 1 atm, and typically 25°C (298 K).
The equilibrium constant (K) represents the concentration ratio of products to reactants at equilibrium.
A large K (greater than 1, especially above 1000) indicates a reaction that favors products.
A small K (less than 1) shows a reaction that favors reactants; K cannot be negative as concentrations are non-negative.
K around 1 suggests a balanced reaction with significant amounts of both products and reactants.

Relationship Between ΔG and K

The equation ΔG° = -RT ln K relates standard Gibbs free energy to the equilibrium constant.
Negative ΔG° indicates a spontaneous reaction under standard conditions, resulting in K > 1 (favoring products).
Positive ΔG° signifies a non-spontaneous reaction, leading to K < 1 (favoring reactants).
When ΔG° = 0, the equilibrium constant K equals 1, which is a rare occurrence.

Catalysts and Enzymes

Catalysts speed up reactions by providing an alternative pathway with lower activation energy.
Lower activation energy allows reactions to proceed more quickly, affecting both forward and reverse directions.
Catalysts are not consumed in the overall reaction and can facilitate multiple reactions without being depleted.
Enzymes function as biological catalysts, repeating the process for successive reactions in living organisms.

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Description

Explore the principles of thermodynamics and kinetics, focusing on Gibbs free energy and its implications for reaction spontaneity. Understand the concepts of exergonic and endergonic reactions, equilibrium, and the significance of the equilibrium constant. This quiz is perfect for students looking to solidify their grasp of these fundamental concepts in chemistry.