Endothermic Exothermic Reactions Difference - Definition, Examples, Important Details

Endothermic Exothermic Reactions Difference - Definition, Examples, Important Details

Edited By Team Careers360 | Updated on Jul 02, 2025 04:32 PM IST

What is Exothermic and Endothermic Reaction?

Various chemical reactions release energy in many forms of heat, light, or sound. This is an exothermic reaction. A surprising response may occur automatically and lead to a random rise or entropy (ΔS> 0) of the system. They are shown to have a negative heat flow (heat is lost around) and down to the enthalpy (ΔH <0). In the lab, a shocking reaction produces heat or explosion. There is another chemical reaction that must absorb energy to continue. This is the end of the body response. Endothermic reactions cannot occur automatically. Work must be done to make this response possible. When the end-reaction reaction absorbs energy, a decrease in temperature is measured during the reaction. Endothermic reaction is characterized by a positive flow of heat (in reaction) and an increase in enthalpy (+ ΔH).

This Story also Contains
  1. What is Exothermic and Endothermic Reaction?
  2. Examples of Endothermic and Exothermic Reactions
  3. Endergonic and Exergonic Reactions
  4. Define Endothermic Reaction.
  5. Define Exothermic Reaction
  6. What is an Endothermic reaction?
  7. How are Endothermic and Exothermic reactions different?
  8. Important details

Also check-

Examples of Endothermic and Exothermic Reactions

Photosynthesis is one of the best examples of an endothermic chemical reaction. In this process, plants usually use energy from the sun to convert carbon dioxide and water into sugars and even oxygen. This reaction usually requires 15MJ of energy (sunlight) for every kilogram of given sugar produced.

sunlight + 6CO2 (g) + H2O (l) = C6H12O6 (aq) + 6O2 (g)

Some examples of endothermic Reactions include:

1.Dissolve ammonium chloride in water

2.Crack of alkanes

3.Nucleosynthesis is heavier than nickel in stars

4.Evaporation of liquid water

5.Melting snow

An example of an exothermic reaction is a mixture of sodium and chlorine to produce table salt. This reaction produces 411 kJ of energy in each salt molecule produced:

Na (s) + 0.5Cl2 (s) = NaCl (s)

Some examples of bizarre processes include:

1.Thermite reaction

2.Neutral reactions (e.g., mixing acid and base to form salt and water)

3.Multiple reaction polymerization

4.Fuel burning

5.Breathing

6.Nuclear closure

7.Iron corrosion (oxidation reaction)

8.Detoxification of acid in water

Shows You Can Do

Many of the most bizarre and end-of-life reactions include toxic chemicals, extreme heat or cold, or waste disposal methods. An example of a shocking quick response is to get rid of the powdery mildew in your hand with a little water.

An example of a simple endothermic reaction is to dissolve potassium chloride (sold as a substitute salt) in your hand with water.

Read more :

NEET Highest Scoring Chapters & Topics
This ebook serves as a valuable study guide for NEET exams, specifically designed to assist students in light of recent changes and the removal of certain topics from the NEET exam.
Download EBook

Endergonic and Exergonic Reactions

Endothermic and exothermic reactions refer to absorption or heat release. There are other forms of energy that can be produced or absorbed by chemical reactions. Examples include light and sound. In general, energy-responsive reactions can be classified as endergonic or exergonic, end-response is an example of an endergonic response. Anxious reaction is an example of a strong response. This article explains various difference between exothermic and endothermic reactions. There are many chemical reactions in Chemistry and they are divided into many small and critical reactions. It is the same with endothermic and exothermic practice in Chemistry.

These release energy in the form of noise, light, cold or heat. In simple terms, the end-of-life reaction receives energy from an environmentally friendly environment. On the other hand, frustrating reactions release the energy of the surrounding system. A common example of an endothermic chemical reaction is photosynthesis. In this process, plants absorb energy from the Sun and then convert the energy into carbon dioxide and water into glucose and oxygen. An example of an exothermic reaction is the chemical reaction between sodium and chlorine, which leads to the formation of sodium chloride (also known as common salt).

Define Endothermic Reaction.

Endothermic Reaction Definition: Endothermic reaction can be defined as a response that requires external energy to proceed. An endothermic reaction is a term that describes the reaction in which a system absorbs energy from its surroundings and environment in the form of heat. A few examples of endothermic processes are photosynthesis, liquid vapor, soluble ice, dry ice, cracking of alkanes, hot rot, ammonium chloride in water and much more.

Define Exothermic Reaction

Exothermic Reaction Definition: A chemical reaction in nature and characterized by the release of energy in the form of heat or light is called an exothermic reaction. Excessive reaction is the opposite of an end-of-life response. It emits energy by light or by ambient temperature. A few examples are neutrality, heat something, oil reaction, dry ice setting, respiration, sulfuric acid solution in water and much more.

What is an Exothermic Reaction reaction?

An exothermic reaction is when energy is released in the form of light or heat. So in a frustrating turn, energy is transferred to the environment rather than taking away the energy in the environment as a response to the end of the body. In a disturbing response, the change in enthalpy (ΔH) will be negative.

Excessive response to chemical reactions involving the release of energy in the form of heat or light. This reaction is counterproductive and can be shown in the chemical equation as follows: Reactants → Products + Energy

Therefore, it can be understood that the total amount of energy required to initiate a complex reaction is less than the amount of energy released by the response. When a calorimeter, a device used to measure the temperature emitted by a chemical reaction, the total amount of heat energy flowing through this device is equal to the magnitude of the total system power switch.

However, it is very difficult to measure or calculate the total amount of energy in a given chemical system. Therefore, the change in power (or enthalpy change, indicated by ΔH) is measured instead. The relationship between the ΔH value and the strength of the response bonds can be given by the following equation.

ΔH = (energy used in the formation of bonds that produce products) - (energy released when active bonds are broken)

Therefore, it can be understood that a random reaction will always have a negative change in enthalpy, e.g. <H <0.

To measure enthalpy change in fire response, calorimeter bombing devices are very suitable.

NCERT Chemistry Notes :

What is an Endothermic reaction?

Endothermic reaction is a chemical reaction in which reactants absorb heat energy from the surrounding environment to form products. This reaction lowers the ambient temperature, thereby creating a cooling effect. Physical processes can be circular as well - Ice cubes absorb heat energy from their sources and melt to form liquids (no broken or synthetic chemical bonds).

When a chemical bond is usually broken, it is even accompanied by some various releases of energy.

The energy supplied / released can be of various types (such as heat, light, and electricity). Endothermic reactions usually involve the formation of chemical bonds by absorbing heat from the surrounding environment. On the other hand, a worrying reaction involves the release of heat energy generated from the bonding of the bonds.

How are Endothermic and Exothermic reactions different?

The words 'Endo' and 'Exo' have Greek roots, meaning 'inside' and 'exit' respectively. As the words show, the main difference between the end-to-end response and respiration is that the first one captures the heat around you and the latter involves heat dissipation.

Important details

Endothermic and exothermic reactions are the only chemical reactions that absorb and release heat, respectively.

A good and best example of an endothermic reaction is photosynthesis.

Heat is an example of an exothermic reaction.

The classification of the response as endo- or exothermic depends on the heat transfer of the net. In any given reaction, heat is absorbed and released. For example, power should be added to the start of the fire to start (lighting the fire with matches), but then more heat is released than needed.

Also read -

Frequently Asked Questions (FAQs)

1. 1.Is it exothermic hot or too cold?

The stressful process releases heat, causing the rapid local temperature to rise. The end-to-end process captures heat and cools the surrounding environment. ”

2. 2.What are exothermic reactions and examples?

Exothermic reactions are defined as heat-responsive reactions and have a common variant of normal enthalpy. Examples of exothermic reactions include any process of fire, metal corrosion and cold water. Amazing reaction is energy that emits energy from the environment in the form of heat.

3. 3.What is the endothermic process?

Endothermic processes

 Melt ice cubes. Melt solid salt. Evaporation of liquid water. Converting snow into water vapor ,melting, boiling, and evaporation, in general, are processes of dehydration.

4. 4.What are three examples of endothermic reactions?

These examples may be labeled as chemical exposures, but are generally considered as end-of-life or heat-absorbing processes:

Melt ice cubes.

Melt solid salt.

Evaporation of liquid water.

5. 5.What happens to the end-of-life process?

In response to power outages, more energy is absorbed when bonds to the reactants are broken than are released when new bonds are built into products. Endothermic reaction is accompanied by a decrease in the temperature of the reaction mixture.

6. 6.Is frying the egg exothermic or endothermic?

Endothermic should be provided with heat and is actually anti-exothermic. The daily reaction is cooking an egg. There should be extra or natural inclusions to cook an egg or other food item.

7. Can you explain why the dissolution of ammonium nitrate in water is endothermic?
The dissolution of ammonium nitrate is endothermic because the energy required to break the ionic bonds in the solid and create hydration shells around the ions is greater than the energy released when these ions interact with water molecules.
8. Can you explain why the evaporation of water is an endothermic process?
Water evaporation is endothermic because energy is required to overcome the intermolecular forces (hydrogen bonds) between water molecules in the liquid state. This energy is absorbed from the surroundings, causing a cooling effect.
9. How can you determine if a reaction is endothermic or exothermic without measuring the temperature change?
You can determine the nature of a reaction by comparing the enthalpy of the products to the reactants. If the enthalpy of the products is higher than the reactants, the reaction is endothermic. If it's lower, the reaction is exothermic.
10. Why are many decomposition reactions endothermic?
Decomposition reactions often break strong bonds in a compound to form simpler substances. This bond breaking requires energy input, making the overall process endothermic.
11. How does the strength of chemical bonds influence whether a reaction is endothermic or exothermic?
Generally, forming stronger bonds releases more energy, while breaking stronger bonds requires more energy. If the bonds formed in the products are stronger than those broken in the reactants, the reaction is likely to be exothermic, and vice versa.
12. Can you explain why the reaction of baking soda and vinegar is exothermic?
The reaction between baking soda (sodium bicarbonate) and vinegar (acetic acid) is exothermic because it involves the formation of more stable products (water, carbon dioxide, and sodium acetate). The energy released during this bond formation exceeds the energy required for the initial bond breaking.
13. Why are neutralization reactions typically exothermic?
Neutralization reactions between acids and bases are usually exothermic because the formation of water molecules from H+ and OH- ions releases energy. This energy release is due to the strong hydrogen bonds formed in water.
14. Why are most synthesis reactions exothermic?
Most synthesis reactions are exothermic because they involve the formation of new, often stronger bonds. The energy released when these bonds form typically exceeds the energy required to break the bonds in the reactants.
15. How do endothermic and exothermic reactions affect the equilibrium constant of a reversible reaction?
For endothermic reactions, increasing temperature shifts the equilibrium to the right (favoring products), increasing the equilibrium constant. For exothermic reactions, increasing temperature shifts the equilibrium to the left (favoring reactants), decreasing the equilibrium constant.
16. How do intermolecular forces affect whether a dissolution process is endothermic or exothermic?
The balance between breaking solute-solute and solvent-solvent interactions (endothermic) and forming new solute-solvent interactions (exothermic) determines whether dissolution is overall endothermic or exothermic. Strong solute-solvent interactions favor exothermic dissolution.
17. How does the concept of Gibbs free energy relate to endothermic and exothermic reactions?
Gibbs free energy (ΔG) combines enthalpy (ΔH) and entropy (ΔS) changes. For a reaction to be spontaneous, ΔG must be negative. Exothermic reactions (negative ΔH) are more likely to have a negative ΔG, while endothermic reactions may be spontaneous if there's a large increase in entropy.
18. How does the concept of entropy relate to whether a reaction is endothermic or exothermic?
While entropy doesn't directly determine if a reaction is endothermic or exothermic, it plays a crucial role in determining spontaneity. Endothermic reactions often increase entropy, which can make them spontaneous despite the unfavorable enthalpy change.
19. Why are most nuclear reactions highly exothermic?
Nuclear reactions, particularly fusion and fission, are highly exothermic because they involve changes in nuclear binding energy. The energy released when forming more stable nuclei far exceeds the energy involved in typical chemical bonds.
20. How do endothermic and exothermic reactions contribute to energy flow in ecosystems?
Endothermic reactions, like photosynthesis, capture and store energy from the sun. Exothermic reactions, like cellular respiration, release this stored energy, allowing it to flow through the ecosystem and drive various life processes.
21. Why is the cracking of hydrocarbons typically an endothermic process?
Cracking hydrocarbons is endothermic because it involves breaking strong carbon-carbon bonds in larger molecules to form smaller molecules. The energy required to break these bonds exceeds the energy released when forming new bonds in the products.
22. How do endothermic and exothermic reactions contribute to climate regulation on Earth?
Endothermic reactions, like the evaporation of water, absorb heat and cool the Earth's surface. Exothermic reactions, like the combustion of fossil fuels, release heat and can contribute to global warming. The balance of these processes plays a crucial role in climate regulation.
23. Can you explain why some exothermic reactions, like rusting, occur slowly?
While rusting (iron oxidation) is exothermic overall, it occurs slowly because it has a high activation energy. The rate of reaction is determined by the activation energy, not by whether the reaction is endothermic or exothermic.
24. Can you explain why some endothermic reactions, like the formation of NO from N2 and O2, occur at high temperatures?
High temperatures provide the necessary energy to overcome the large activation energy barrier in endothermic reactions. In the case of NO formation, high temperatures also increase the entropy of the system, making the reaction more favorable according to the Gibbs free energy equation.
25. What is the fundamental difference between endothermic and exothermic reactions?
Endothermic reactions absorb heat from the surroundings, while exothermic reactions release heat to the surroundings. In endothermic reactions, the system's energy increases, and in exothermic reactions, the system's energy decreases.
26. How does the enthalpy change (ΔH) differ for endothermic and exothermic reactions?
For endothermic reactions, the enthalpy change (ΔH) is positive, indicating heat absorption. For exothermic reactions, ΔH is negative, indicating heat release to the surroundings.
27. Why do exothermic reactions often feel warm to the touch?
Exothermic reactions release heat to the surroundings, which can be felt as warmth. The energy released during the reaction increases the kinetic energy of nearby molecules, raising the temperature of the immediate environment.
28. How do endothermic and exothermic reactions affect the temperature of their surroundings?
Endothermic reactions decrease the temperature of their surroundings as they absorb heat, while exothermic reactions increase the temperature of their surroundings as they release heat.
29. What role does bond breaking and bond formation play in determining whether a reaction is endothermic or exothermic?
Bond breaking is an endothermic process, while bond formation is exothermic. The overall energy change of a reaction depends on whether more energy is required to break bonds or released when new bonds form. If bond breaking requires more energy, the reaction is endothermic; if bond formation releases more energy, the reaction is exothermic.
30. How does activation energy relate to endothermic and exothermic reactions?
Both endothermic and exothermic reactions require activation energy to initiate. However, in exothermic reactions, the energy released is greater than the activation energy, while in endothermic reactions, the energy absorbed is greater than the activation energy.
31. Can an endothermic reaction occur spontaneously?
Yes, an endothermic reaction can occur spontaneously if the increase in entropy (disorder) of the system is large enough to overcome the unfavorable enthalpy change. This is more likely at higher temperatures.
32. Why are most combustion reactions exothermic?
Combustion reactions are typically exothermic because they involve the formation of strong bonds in the products (like CO2 and H2O) from weaker bonds in the reactants. The energy released from forming these strong bonds exceeds the energy required to break the bonds in the reactants.
33. How does Le Chatelier's principle apply to endothermic and exothermic reactions?
According to Le Chatelier's principle, increasing the temperature favors the endothermic direction of a reaction, while decreasing the temperature favors the exothermic direction. This is because the system will shift to counteract the imposed change.
34. Why are endothermic reactions often associated with an increase in disorder (entropy)?
Endothermic reactions often increase disorder because they typically involve breaking bonds or increasing the number of particles, which leads to greater molecular motion and more ways to distribute energy, thus increasing entropy.
35. Can a reaction be both endothermic and exothermic?
A single reaction cannot be both endothermic and exothermic simultaneously. However, a process may involve multiple steps, some of which are endothermic and others exothermic. The overall process is classified based on the net energy change.
36. What is the relationship between bond energy and the endo/exothermic nature of a reaction?
The net difference between the energy required to break bonds in the reactants and the energy released when forming new bonds in the products determines whether a reaction is endothermic or exothermic. If more energy is released in bond formation than consumed in bond breaking, the reaction is exothermic, and vice versa.
37. How do endothermic and exothermic reactions relate to the concepts of system and surroundings in thermodynamics?
In thermodynamics, the system is the reaction itself, while the surroundings are everything else. Endothermic reactions absorb heat from the surroundings into the system, while exothermic reactions release heat from the system to the surroundings.
38. How does the concept of bond enthalpy help predict whether a reaction will be endothermic or exothermic?
By comparing the sum of bond enthalpies of bonds broken in reactants to those formed in products, we can predict the reaction's nature. If the energy released by bond formation exceeds that required for bond breaking, the reaction is exothermic, and vice versa.
39. Can you explain why the formation of ionic compounds from their elements is typically exothermic?
The formation of ionic compounds is usually exothermic because the energy released during electron transfer and the formation of the ionic lattice typically exceeds the energy required to ionize the atoms. The strong electrostatic attractions in the ionic lattice contribute significantly to the energy release.
40. Can you explain why ice melting is an endothermic process?
Ice melting is endothermic because it requires energy input to break the hydrogen bonds between water molecules in the solid state. This energy is absorbed from the surroundings, causing a cooling effect.
41. How do endothermic and exothermic reactions affect the internal energy of a system?
Endothermic reactions increase the internal energy of a system as they absorb heat, while exothermic reactions decrease the internal energy of a system as they release heat.
42. Why are some endothermic reactions, like photosynthesis, crucial for life on Earth?
Endothermic reactions like photosynthesis are crucial because they store energy from the sun in chemical bonds. This stored energy can later be released through exothermic reactions (like cellular respiration) to power life processes.
43. How do catalysts affect the endo/exothermic nature of a reaction?
Catalysts do not change whether a reaction is endothermic or exothermic. They lower the activation energy for both forward and reverse reactions equally, allowing the reaction to reach equilibrium faster without affecting the overall energy change.
44. How does the concept of heat capacity relate to endothermic and exothermic reactions?
Heat capacity affects how much the temperature changes during a reaction. A substance with high heat capacity will show a smaller temperature change for the same amount of heat absorbed or released compared to a substance with low heat capacity.
45. How do endothermic and exothermic reactions affect the internal pressure of a closed system?
In a closed system, endothermic reactions tend to decrease the internal pressure as they absorb heat and potentially increase volume. Exothermic reactions tend to increase internal pressure as they release heat, potentially causing expansion.
46. How do endothermic and exothermic reactions affect the speed of sound in gases?
Exothermic reactions in gases increase the speed of sound by raising the temperature, which increases molecular velocity. Endothermic reactions decrease the speed of sound by lowering the temperature and reducing molecular velocity.

Articles

Back to top