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Exothermic & endothermic reactions

5 Differences Between Exothermic and Endothermic Reactions with Examples

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5 Differences Between Exothermic and Endothermic Reactions with Examples
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Reuben Cowell

@reubencowell

·

103 Followers

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Understanding chemical reactions and their energy changes is crucial for chemistry students. Exothermic and endothermic reactions form the foundation of energy transfer in chemical processes, with distinct characteristics and real-world applications.

• Energy transfer in chemical reactions involves either releasing energy to surroundings (exothermic) or absorbing energy from surroundings (endothermic)

• Reaction profiles demonstrate the energy changes throughout reactions, including activation energy and overall energy change

• Bond breaking and formation processes determine whether a reaction is exothermic or endothermic

• Practical applications include hand warmers (exothermic) and instant ice packs (endothermic)

06/03/2023

362

1.5.1 Exothermic and Endothermic Reactions ✓ Chemistry MOC Energy Transfer During Exothermic and Endothermic Reactions Whenever there are ch

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Endothermic Reactions and Reaction Profiles

Endothermic Reactions

Endothermic reactions absorb energy from the surroundings, often resulting in a temperature decrease. These reactions are less common than exothermic ones.

Definition: An endothermic reaction is a reaction that takes in energy from the surroundings.

Example: The reaction between citric acid and sodium hydrogencarbonate is an endothermic process.

Other examples of endothermic reactions include:

  • Thermal decomposition

Highlight: Endothermic reactions have practical applications, such as in instant ice packs that cool without refrigeration.

Reaction Profiles

Reaction profiles visually represent the energy changes during chemical reactions. They show:

  • Relative energies of reactants and products
  • Energy changes throughout the reaction progress
  • Whether a reaction is exothermic or endothermic

Vocabulary: Activation energy is the minimum amount of energy needed for reactants to collide and initiate a reaction.

Reaction profiles illustrate key differences between exothermic and endothermic reactions:

  • Exothermic reactions: Energy of products is lower than reactants, resulting in a negative overall energy change
  • Endothermic reactions: Energy of products is higher than reactants, leading to a positive overall energy change

Highlight: Reaction profiles provide a visual representation of energy changes in chemistry, helping to distinguish between exothermic and endothermic reactions.

1.5.1 Exothermic and Endothermic Reactions ✓ Chemistry MOC Energy Transfer During Exothermic and Endothermic Reactions Whenever there are ch

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Energy Changes and Bond Energies in Chemical Reactions

Energy Changes in Reactions

Chemical reactions involve breaking existing bonds and forming new ones, which contributes to the overall energy change:

  • Bond breaking: An endothermic process requiring energy input
  • Bond formation: An exothermic process releasing energy

Highlight: The balance between energy required for bond breaking and energy released during bond formation determines whether a reaction is overall exothermic or endothermic.

Bond Energies and Energy Calculations

Every chemical bond has an associated bond energy that varies depending on the compound. These known bond energies can be used to calculate the overall energy change for a reaction.

Definition: The overall energy change is the sum of the energies needed to break bonds in the reactants minus the energy released when new bonds are formed in the products.

To calculate the energy change for a reaction:

  1. Determine the energy required to break original bonds
  2. Calculate the energy released by forming new bonds
  3. Subtract the energy to break bonds from the energy to form new bonds

Highlight: Understanding bond energy calculations is crucial for predicting and analyzing energy changes in chemistry.

This approach allows for the quantitative analysis of energy changes in reactions, providing insights into the thermodynamics of chemical processes.

1.5.1 Exothermic and Endothermic Reactions ✓ Chemistry MOC Energy Transfer During Exothermic and Endothermic Reactions Whenever there are ch

View

Energy Changes and Reaction Profiles

The detailed examination of reaction profiles and energy changes in chemistry reveals the relationship between reactants and products in terms of energy.

Definition: Reaction profiles show energy changes throughout a reaction's progress, with energy on the y-axis and reaction progress on the x-axis.

Highlight: In exothermic reactions, products have lower energy than reactants (negative energy change), while in endothermic reactions, products have higher energy than reactants (positive energy change).

Example: How to calculate energy change in chemistry involves understanding bond breaking (endothermic) and bond forming (exothermic) processes.

1.5.1 Exothermic and Endothermic Reactions ✓ Chemistry MOC Energy Transfer During Exothermic and Endothermic Reactions Whenever there are ch

View

Energy Transfer in Exothermic and Endothermic Reactions

Chemical reactions involve energy changes as chemicals store varying amounts of energy. The energy transfer between reactants, products, and surroundings determines whether a reaction is exothermic or endothermic.

Exothermic Reactions

Exothermic reactions transfer energy to the surroundings, typically manifested as a temperature rise. Common examples include:

  • Burning fuels
  • Neutralization reactions
  • Many oxidation reactions

Definition: An exothermic reaction is a reaction that transfers energy to the surroundings.

Example: Hand warmers and heating systems utilize exothermic reactions to generate heat.

Practical Measurement

To measure energy transfer and determine if a reaction is exothermic or endothermic:

  1. Measure the initial temperature of reagents
  2. Place them in an insulated environment
  3. Allow the reaction to occur
  4. Measure the final temperature

Highlight: This practical method helps identify whether a reaction is exothermic or endothermic based on temperature changes.

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Subjects

/

Chemistry

/

Chemical reactions

/

Exothermic & endothermic reactions

5 Differences Between Exothermic and Endothermic Reactions with Examples

user profile picture

Reuben Cowell

@reubencowell

·

103 Followers

Follow

Understanding chemical reactions and their energy changes is crucial for chemistry students. Exothermic and endothermic reactions form the foundation of energy transfer in chemical processes, with distinct characteristics and real-world applications.

• Energy transfer in chemical reactions involves either releasing energy to surroundings (exothermic) or absorbing energy from surroundings (endothermic)

• Reaction profiles demonstrate the energy changes throughout reactions, including activation energy and overall energy change

• Bond breaking and formation processes determine whether a reaction is exothermic or endothermic

• Practical applications include hand warmers (exothermic) and instant ice packs (endothermic)

06/03/2023

362

 

10/11

 

Chemistry

11

1.5.1 Exothermic and Endothermic Reactions ✓ Chemistry MOC Energy Transfer During Exothermic and Endothermic Reactions Whenever there are ch

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Endothermic Reactions and Reaction Profiles

Endothermic Reactions

Endothermic reactions absorb energy from the surroundings, often resulting in a temperature decrease. These reactions are less common than exothermic ones.

Definition: An endothermic reaction is a reaction that takes in energy from the surroundings.

Example: The reaction between citric acid and sodium hydrogencarbonate is an endothermic process.

Other examples of endothermic reactions include:

  • Thermal decomposition

Highlight: Endothermic reactions have practical applications, such as in instant ice packs that cool without refrigeration.

Reaction Profiles

Reaction profiles visually represent the energy changes during chemical reactions. They show:

  • Relative energies of reactants and products
  • Energy changes throughout the reaction progress
  • Whether a reaction is exothermic or endothermic

Vocabulary: Activation energy is the minimum amount of energy needed for reactants to collide and initiate a reaction.

Reaction profiles illustrate key differences between exothermic and endothermic reactions:

  • Exothermic reactions: Energy of products is lower than reactants, resulting in a negative overall energy change
  • Endothermic reactions: Energy of products is higher than reactants, leading to a positive overall energy change

Highlight: Reaction profiles provide a visual representation of energy changes in chemistry, helping to distinguish between exothermic and endothermic reactions.

1.5.1 Exothermic and Endothermic Reactions ✓ Chemistry MOC Energy Transfer During Exothermic and Endothermic Reactions Whenever there are ch

Sign up to see the content. It's free!

Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

Energy Changes and Bond Energies in Chemical Reactions

Energy Changes in Reactions

Chemical reactions involve breaking existing bonds and forming new ones, which contributes to the overall energy change:

  • Bond breaking: An endothermic process requiring energy input
  • Bond formation: An exothermic process releasing energy

Highlight: The balance between energy required for bond breaking and energy released during bond formation determines whether a reaction is overall exothermic or endothermic.

Bond Energies and Energy Calculations

Every chemical bond has an associated bond energy that varies depending on the compound. These known bond energies can be used to calculate the overall energy change for a reaction.

Definition: The overall energy change is the sum of the energies needed to break bonds in the reactants minus the energy released when new bonds are formed in the products.

To calculate the energy change for a reaction:

  1. Determine the energy required to break original bonds
  2. Calculate the energy released by forming new bonds
  3. Subtract the energy to break bonds from the energy to form new bonds

Highlight: Understanding bond energy calculations is crucial for predicting and analyzing energy changes in chemistry.

This approach allows for the quantitative analysis of energy changes in reactions, providing insights into the thermodynamics of chemical processes.

1.5.1 Exothermic and Endothermic Reactions ✓ Chemistry MOC Energy Transfer During Exothermic and Endothermic Reactions Whenever there are ch

Sign up to see the content. It's free!

Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

Energy Changes and Reaction Profiles

The detailed examination of reaction profiles and energy changes in chemistry reveals the relationship between reactants and products in terms of energy.

Definition: Reaction profiles show energy changes throughout a reaction's progress, with energy on the y-axis and reaction progress on the x-axis.

Highlight: In exothermic reactions, products have lower energy than reactants (negative energy change), while in endothermic reactions, products have higher energy than reactants (positive energy change).

Example: How to calculate energy change in chemistry involves understanding bond breaking (endothermic) and bond forming (exothermic) processes.

1.5.1 Exothermic and Endothermic Reactions ✓ Chemistry MOC Energy Transfer During Exothermic and Endothermic Reactions Whenever there are ch

Sign up to see the content. It's free!

Access to all documents

Improve your grades

Join milions of students

By signing up you accept Terms of Service and Privacy Policy

Energy Transfer in Exothermic and Endothermic Reactions

Chemical reactions involve energy changes as chemicals store varying amounts of energy. The energy transfer between reactants, products, and surroundings determines whether a reaction is exothermic or endothermic.

Exothermic Reactions

Exothermic reactions transfer energy to the surroundings, typically manifested as a temperature rise. Common examples include:

  • Burning fuels
  • Neutralization reactions
  • Many oxidation reactions

Definition: An exothermic reaction is a reaction that transfers energy to the surroundings.

Example: Hand warmers and heating systems utilize exothermic reactions to generate heat.

Practical Measurement

To measure energy transfer and determine if a reaction is exothermic or endothermic:

  1. Measure the initial temperature of reagents
  2. Place them in an insulated environment
  3. Allow the reaction to occur
  4. Measure the final temperature

Highlight: This practical method helps identify whether a reaction is exothermic or endothermic based on temperature changes.

Similar content

Chemistry - GCSE Chemistry C6: Rate and extent of chemical change

GCSE Chemistry C6: Rate and extent of chemical change summary mindmap

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Know GCSE Chemistry C6: Rate and extent of chemical change thumbnail

Chemistry - energy changes AQA GCSE summary notes

Great for memorising energy changes, blurting it and testing your knowledge 🫶🏼 hope this helps someone as much as it helped me.

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568

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Know energy changes AQA GCSE summary notes thumbnail

Can't find what you're looking for? Explore other subjects.

Knowunity is the #1 education app in five European countries

Knowunity has been named a featured story on Apple and has regularly topped the app store charts in the education category in Germany, Italy, Poland, Switzerland, and the United Kingdom. Join Knowunity today and help millions of students around the world.

Ranked #1 Education App

Download in

Google Play

Download in

App Store

Knowunity is the #1 education app in five European countries

4.9+

Average app rating

15 M

Pupils love Knowunity

#1

In education app charts in 12 countries

950 K+

Students have uploaded notes

Still not convinced? See what other students are saying...

iOS User

I love this app so much, I also use it daily. I recommend Knowunity to everyone!!! I went from a D to an A with it :D

Philip, iOS User

The app is very simple and well designed. So far I have always found everything I was looking for :D

Lena, iOS user

I love this app ❤️ I actually use it every time I study.