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Chemical Kinetics vs. Thermodynamics: What's the Difference?

Edited by Aimie Carlson || By Janet White || Published on December 25, 2023
Chemical kinetics studies reaction rates and mechanisms, while thermodynamics examines energy changes and equilibrium in chemical processes.

Key Differences

Chemical kinetics focuses on the speed of chemical reactions and the steps involved in these reactions. In contrast, thermodynamics deals with the overall energy changes that occur during chemical reactions, particularly regarding the transfer and transformation of energy.
Chemical kinetics provides insights into how quickly a reaction proceeds, while thermodynamics determines whether a reaction is energetically favorable or not. Kinetics is about the "how fast," whereas thermodynamics is about the "if" a reaction can occur.
Chemical kinetics involves studying factors like concentration, temperature, and catalysts that affect reaction rates. Thermodynamics, however, is concerned with concepts like enthalpy, entropy, and Gibbs free energy, which describe the energy state of a system.
In chemical kinetics, the rate laws and reaction mechanisms are pivotal concepts. On the other hand, thermodynamics revolves around the laws of thermodynamics and their application in predicting the spontaneity of chemical reactions.
Chemical kinetics is the branch of chemistry that deals with the pace of reactions and the sequence of molecular events, while thermodynamics focuses on the energy aspects and the final state of chemical processes.

Comparison Chart

Main Focus

Speed and mechanism of reactions
Energy changes and equilibrium

Key Concepts

Reaction rates, rate laws
Enthalpy, entropy, Gibbs free energy


How fast a reaction proceeds
If a reaction is energetically possible

Influencing Factors

Concentration, temperature, catalysts
Temperature, pressure, volume

Governing Principles

Rate laws and activation energy
First and second laws of thermodynamics

Chemical Kinetics and Thermodynamics Definitions

Chemical Kinetics

It examines how reaction conditions influence the speed of reactions.
Chemical kinetics explains why increasing temperature speeds up a reaction.


Thermodynamics is the study of energy transformations in chemical processes.
Thermodynamics helps in understanding how energy is conserved in chemical reactions.

Chemical Kinetics

Chemical kinetics also looks into the energy barriers of reactions.
Chemical kinetics reveals the activation energy required for a fuel combustion reaction.


It includes studying the relationship between heat, work, and temperature.
Thermodynamics explains how heat converts to work in an engine.

Chemical Kinetics

It involves the calculation of reaction rates and understanding catalysts.
Through chemical kinetics, the effect of a catalyst on ammonia synthesis is quantified.


It assesses the direction and extent of energy transfer.
In thermodynamics, the concept of entropy explains disorder in a system.

Chemical Kinetics

Chemical kinetics investigates the molecular pathways of reactions.
The field of chemical kinetics has elucidated the complex steps of enzyme reactions.


Thermodynamics determines the spontaneity of reactions.
Using thermodynamics, chemists can predict if a reaction will occur naturally.

Chemical Kinetics

Chemical kinetics studies the rate at which chemical reactions occur.
In chemical kinetics, the decomposition of hydrogen peroxide is often examined.


Thermodynamics involves the laws governing energy conservation and efficiency.
The first law of thermodynamics is crucial in understanding energy balance in chemical reactions.


(used with a sing. verb) Physics that deals with the relationships and conversions between heat and other forms of energy.


(used with a pl. verb) Thermodynamic phenomena and processes.


(physics) The science of the conversions between heat and other forms of energy.


The science which treats of the mechanical action or relations of heat.


The branch of physics concerned with the conversion of different forms of energy


What does thermodynamics study?

It studies energy changes and equilibrium in chemical processes.

What is chemical kinetics?

It's the study of reaction rates and mechanisms.

How does thermodynamics assess reaction spontaneity?

By calculating Gibbs free energy.

Can thermodynamics predict if a reaction will occur?

Yes, through concepts like Gibbs free energy.

How does temperature affect chemical kinetics?

Higher temperatures usually increase reaction rates.

What are rate laws in chemical kinetics?

Equations that relate reaction rate to reactant concentrations.

What is entropy in thermodynamics?

A measure of disorder or randomness in a system.

Are catalysts part of chemical kinetics study?

Yes, they are crucial in affecting reaction rates.

How does pressure influence thermodynamics?

It affects the equilibrium and energy state of reactions.

Are reaction mechanisms part of chemical kinetics?

Yes, they describe the steps in a reaction.

Can kinetics predict the yield of a chemical reaction?

No, it focuses on reaction rate, not yield.

Is the concept of enthalpy part of thermodynamics?

Yes, it relates to heat changes in reactions.

What is activation energy in chemical kinetics?

The minimum energy required to start a reaction.

How does a catalyst work, according to chemical kinetics?

By lowering the activation energy of a reaction.

Can thermodynamics determine reaction speed?

No, it focuses on energy, not speed.

What is the second law of thermodynamics?

It states that the total entropy of an isolated system can never decrease over time.

Does chemical kinetics consider the energy of reactions?

It mainly focuses on the speed, not energy.

What role does temperature play in thermodynamics?

It influences the energy state and equilibrium.

How do reaction intermediates relate to chemical kinetics?

They are transient species in a reaction mechanism.

Is calculating entropy change part of thermodynamics?

Yes, it's key in determining reaction spontaneity.
About Author
Written by
Janet White
Janet White has been an esteemed writer and blogger for Difference Wiki. Holding a Master's degree in Science and Medical Journalism from the prestigious Boston University, she has consistently demonstrated her expertise and passion for her field. When she's not immersed in her work, Janet relishes her time exercising, delving into a good book, and cherishing moments with friends and family.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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