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23
1
Aysha Akmal
24/01/2023
Chemistry
Edexcel A Level Chemistry - Topic 11 Further Equilibrium
520
•
24 Jan 2023
•
Aysha Akmal
@ayshakmal
A comprehensive guide to equilibrium constant calculationsand related concepts... Show more
This section delves deeper into the process of calculating Kc and introduces the concept of heterogeneous equilibria.
To calculate Kc:
Example: For the reaction 2NOCl(g) ⇌ 2NO(g) + Cl₂(g) Given: 1.00 mol NOCl in 0.50 dm³ flask, 0.33 mol NO at equilibrium Kc = [NO]² [Cl₂] / [NOCl]² = 0.0800 mol dm⁻³
Heterogeneous equilibria involve substances in different phases. In these systems, solids and pure liquids are not included in the Kc expression as their concentrations remain effectively constant.
Highlight: For heterogeneous equilibria, only include gases and aqueous species in the Kc expression.
Example: For CaCO₃(s) ⇌ CaO(s) + CO₂(g), Kc = [CO₂]
This simplification is due to the constant density of solids and pure liquids, which makes their concentrations invariant in the equilibrium expression.
This section introduces the concept of Kp, which is used for gaseous equilibria where partial pressures are more easily measured than concentrations.
Kp is expressed using partial pressures of gases instead of concentrations:
For aA(g) + bB(g) ⇌ cC(g) + dD(g), Kp = (P_C^c × P_D^d) / (P_A^a × P_B^b)
Where P_A, P_B, P_C, and P_D are the partial pressures of gases A, B, C, and D respectively.
Vocabulary: Mole fraction - The proportion of a particular gas in a mixture, calculated as (moles of gas) / (total moles of all gases).
Vocabulary: Partial pressure - The pressure exerted by a single gas in a mixture, calculated as (mole fraction) × (total pressure).
To calculate Kp:
Example: For N₂(g) + 3H₂(g) ⇌ 2NH₃(g) Given: 2.15 mol N₂, 6.75 mol H₂, 1.41 mol NH₃, total pressure 10.0 atm Calculate mole fractions, then partial pressures, and finally Kp
Understanding Kp is crucial for analyzing gaseous equilibria and complements the use of Kc for solution-based systems.
This section would typically discuss how temperature changes affect equilibrium constants and the position of equilibrium. However, the provided transcript does not contain specific information on this topic.
Highlight: The effects of temperature on equilibrium constants are an important aspect of chemical equilibria, but are not covered in the given material.
In general, temperature changes can shift the equilibrium position and alter the value of the equilibrium constant. This relationship is described by Le Chatelier's Principle and the van 't Hoff equation.
This section would usually provide additional practice problems and real-world applications of equilibrium constant calculations. However, the given transcript does not include such content.
Applying equilibrium concepts to practical situations helps reinforce understanding and demonstrates the relevance of these calculations in various fields of chemistry and chemical engineering.
Highlight: Practice problems are essential for mastering equilibrium constant calculations and understanding how to apply these concepts in different scenarios.
Students are encouraged to seek additional resources for practice problems related to Kc and Kp calculations, as well as explore how these concepts are used in industrial processes and environmental chemistry.
Page 5: Effects of Changing Conditions
This page examines how various factors affect equilibrium constants and positions.
Definition: Le Chatelier's Principle explains how systems respond to changes in conditions.
Example: 2CrO₄²⁻(aq) + 2H⁺(aq) ⇌ Cr₂O₇²⁻(aq) + H₂O(l) demonstrates how concentration changes affect equilibrium.
Highlight: Changing concentration does not alter Kc value as long as temperature remains constant.
The equilibrium law is a fundamental concept in chemistry that describes the state of a reversible reaction when the forward and reverse rates are equal. This section introduces the equilibrium constant Kc and its calculation.
For a general reaction aA + bB ⇌ cC + dD, the equilibrium constant Kc is expressed as:
Kc = [C]^c [D]^d / [A]^a [B]^b
Where [A], [B], [C], and [D] represent the equilibrium concentrations of reactants and products.
Highlight: The equilibrium constant Kc is only valid for systems at constant temperature.
Example: For the reaction CH₃CO₂H (aq) + C₂H₅OH (aq) ⇌ CH₃CO₂C₂H₅ (aq) + H₂O (l), Kc = [CH₃CO₂C₂H₅ (aq)] [H₂O (l)] / [CH₃CO₂H (aq)] [C₂H₅OH (aq)]
The units of Kc depend on the stoichiometry of the reaction. In some cases, Kc may be unitless.
Vocabulary: ICE table - A method for organizing Initial, Change, and Equilibrium concentrations in equilibrium calculations.
The value of Kc provides information about the position of equilibrium:
Definition: Equilibrium position - The relative amounts of reactants and products present when a system reaches equilibrium.
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Anna
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Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
Aysha Akmal
@ayshakmal
A comprehensive guide to equilibrium constant calculations and related concepts in chemistry, focusing on Kc and Kp calculations, heterogeneous equilibria, and the effects of changing conditions.
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This section delves deeper into the process of calculating Kc and introduces the concept of heterogeneous equilibria.
To calculate Kc:
Example: For the reaction 2NOCl(g) ⇌ 2NO(g) + Cl₂(g) Given: 1.00 mol NOCl in 0.50 dm³ flask, 0.33 mol NO at equilibrium Kc = [NO]² [Cl₂] / [NOCl]² = 0.0800 mol dm⁻³
Heterogeneous equilibria involve substances in different phases. In these systems, solids and pure liquids are not included in the Kc expression as their concentrations remain effectively constant.
Highlight: For heterogeneous equilibria, only include gases and aqueous species in the Kc expression.
Example: For CaCO₃(s) ⇌ CaO(s) + CO₂(g), Kc = [CO₂]
This simplification is due to the constant density of solids and pure liquids, which makes their concentrations invariant in the equilibrium expression.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
This section introduces the concept of Kp, which is used for gaseous equilibria where partial pressures are more easily measured than concentrations.
Kp is expressed using partial pressures of gases instead of concentrations:
For aA(g) + bB(g) ⇌ cC(g) + dD(g), Kp = (P_C^c × P_D^d) / (P_A^a × P_B^b)
Where P_A, P_B, P_C, and P_D are the partial pressures of gases A, B, C, and D respectively.
Vocabulary: Mole fraction - The proportion of a particular gas in a mixture, calculated as (moles of gas) / (total moles of all gases).
Vocabulary: Partial pressure - The pressure exerted by a single gas in a mixture, calculated as (mole fraction) × (total pressure).
To calculate Kp:
Example: For N₂(g) + 3H₂(g) ⇌ 2NH₃(g) Given: 2.15 mol N₂, 6.75 mol H₂, 1.41 mol NH₃, total pressure 10.0 atm Calculate mole fractions, then partial pressures, and finally Kp
Understanding Kp is crucial for analyzing gaseous equilibria and complements the use of Kc for solution-based systems.
This section would typically discuss how temperature changes affect equilibrium constants and the position of equilibrium. However, the provided transcript does not contain specific information on this topic.
Highlight: The effects of temperature on equilibrium constants are an important aspect of chemical equilibria, but are not covered in the given material.
In general, temperature changes can shift the equilibrium position and alter the value of the equilibrium constant. This relationship is described by Le Chatelier's Principle and the van 't Hoff equation.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
This section would usually provide additional practice problems and real-world applications of equilibrium constant calculations. However, the given transcript does not include such content.
Applying equilibrium concepts to practical situations helps reinforce understanding and demonstrates the relevance of these calculations in various fields of chemistry and chemical engineering.
Highlight: Practice problems are essential for mastering equilibrium constant calculations and understanding how to apply these concepts in different scenarios.
Students are encouraged to seek additional resources for practice problems related to Kc and Kp calculations, as well as explore how these concepts are used in industrial processes and environmental chemistry.
Page 5: Effects of Changing Conditions
This page examines how various factors affect equilibrium constants and positions.
Definition: Le Chatelier's Principle explains how systems respond to changes in conditions.
Example: 2CrO₄²⁻(aq) + 2H⁺(aq) ⇌ Cr₂O₇²⁻(aq) + H₂O(l) demonstrates how concentration changes affect equilibrium.
Highlight: Changing concentration does not alter Kc value as long as temperature remains constant.
Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
The equilibrium law is a fundamental concept in chemistry that describes the state of a reversible reaction when the forward and reverse rates are equal. This section introduces the equilibrium constant Kc and its calculation.
For a general reaction aA + bB ⇌ cC + dD, the equilibrium constant Kc is expressed as:
Kc = [C]^c [D]^d / [A]^a [B]^b
Where [A], [B], [C], and [D] represent the equilibrium concentrations of reactants and products.
Highlight: The equilibrium constant Kc is only valid for systems at constant temperature.
Example: For the reaction CH₃CO₂H (aq) + C₂H₅OH (aq) ⇌ CH₃CO₂C₂H₅ (aq) + H₂O (l), Kc = [CH₃CO₂C₂H₅ (aq)] [H₂O (l)] / [CH₃CO₂H (aq)] [C₂H₅OH (aq)]
The units of Kc depend on the stoichiometry of the reaction. In some cases, Kc may be unitless.
Vocabulary: ICE table - A method for organizing Initial, Change, and Equilibrium concentrations in equilibrium calculations.
The value of Kc provides information about the position of equilibrium:
Definition: Equilibrium position - The relative amounts of reactants and products present when a system reaches equilibrium.
Our AI Companion is a student-focused AI tool that offers more than just answers. Built on millions of Knowunity resources, it provides relevant information, personalised study plans, quizzes, and content directly in the chat, adapting to your individual learning journey.
You can download the app from Google Play Store and Apple App Store.
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
App Store
Google Play
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
The app is very easy to use and well designed. I have found everything I was looking for so far and have been able to learn a lot from the presentations! I will definitely use the app for a class assignment! And of course it also helps a lot as an inspiration.
Stefan S
iOS user
This app is really great. There are so many study notes and help [...]. My problem subject is French, for example, and the app has so many options for help. Thanks to this app, I have improved my French. I would recommend it to anyone.
Samantha Klich
Android user
Wow, I am really amazed. I just tried the app because I've seen it advertised many times and was absolutely stunned. This app is THE HELP you want for school and above all, it offers so many things, such as workouts and fact sheets, which have been VERY helpful to me personally.
Anna
iOS user
Best app on earth! no words because it’s too good
Thomas R
iOS user
Just amazing. Let's me revise 10x better, this app is a quick 10/10. I highly recommend it to anyone. I can watch and search for notes. I can save them in the subject folder. I can revise it any time when I come back. If you haven't tried this app, you're really missing out.
Basil
Android user
This app has made me feel so much more confident in my exam prep, not only through boosting my own self confidence through the features that allow you to connect with others and feel less alone, but also through the way the app itself is centred around making you feel better. It is easy to navigate, fun to use, and helpful to anyone struggling in absolutely any way.
David K
iOS user
The app's just great! All I have to do is enter the topic in the search bar and I get the response real fast. I don't have to watch 10 YouTube videos to understand something, so I'm saving my time. Highly recommended!
Sudenaz Ocak
Android user
In school I was really bad at maths but thanks to the app, I am doing better now. I am so grateful that you made the app.
Greenlight Bonnie
Android user
very reliable app to help and grow your ideas of Maths, English and other related topics in your works. please use this app if your struggling in areas, this app is key for that. wish I'd of done a review before. and it's also free so don't worry about that.
Rohan U
Android user
I know a lot of apps use fake accounts to boost their reviews but this app deserves it all. Originally I was getting 4 in my English exams and this time I got a grade 7. I didn’t even know about this app three days until the exam and it has helped A LOT. Please actually trust me and use it as I’m sure you too will see developments.
Xander S
iOS user
THE QUIZES AND FLASHCARDS ARE SO USEFUL AND I LOVE THE SCHOOLGPT. IT ALSO IS LITREALLY LIKE CHATGPT BUT SMARTER!! HELPED ME WITH MY MASCARA PROBLEMS TOO!! AS WELL AS MY REAL SUBJECTS ! DUHHH 😍😁😲🤑💗✨🎀😮
Elisha
iOS user
This apps acc the goat. I find revision so boring but this app makes it so easy to organize it all and then you can ask the freeeee ai to test yourself so good and you can easily upload your own stuff. highly recommend as someone taking mocks now
Paul T
iOS user
