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Rates of Reaction
469
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9 Jul 2025
•
How Concentration and Temperature Affect Reaction Rates for Kids
Gracey
@gracey_irtg
Rate-Concentration Graphs and Advanced Concepts
This page expands on rate-concentration graphs for different reaction orders and introduces more advanced concepts in chemical kinetics.
For zero-order reactions, the rate-concentration graph is a horizontal line, as the rate is constant regardless of concentration. The rate equation for a zero-order reaction is:
Example: rate = k⁰ = k
For first-order reactions, the rate-concentration graph is a straight line passing through the origin, with the gradient equal to the rate constant k. The rate equation for a first-order reaction is:
Example: rate = k¹
Second-order reactions have a more complex rate-concentration relationship, and the rate constant cannot be directly determined from the graph. The rate equation for a second-order reaction is:
Example: rate = k²
The page then introduces the concept of clock reactions, where the time from the start to a visual change is measured and assumed to represent the initial rate.
Definition: Rate Determining Step: The slowest step in a reaction mechanism, which determines the overall reaction rate.
The rate equation only includes reacting species involved in the rate-determining step.
The Arrhenius equation is introduced, relating reaction rate to temperature and activation energy:
Example: ln k = -Ea/RT + ln A
Where:
- k is the rate constant
- Ea is the activation energy
- R is the gas constant
- T is the temperature
- A is the pre-exponential factor
Highlight: The Arrhenius equation takes into account the frequency of collisions with the correct orientation and represents the proportion of molecules that exceed the activation energy and have sufficient energy for a reaction to take place.
The page concludes by showing how to determine the activation energy from an Arrhenius plot, where the gradient is equal to -Ea/R.
Rates of Reaction
This page introduces the concept of reaction rates and explores different reaction orders. It explains how concentration affects reaction rate for zero, first, and second-order reactions.
The rate of a reaction is defined as the quantity reacted or produced over time, or the change in concentration over time. The page then delves into the characteristics of different reaction orders:
Definition: Zero-order reaction: The concentration of the reactant has no effect on the rate.
Definition: First-order reaction: The rate depends on the reactant concentration to the power of 1. If the concentration doubles, the reaction rate increases by a factor of 2.
Definition: Second-order reaction: The rate depends on the concentration raised to the power of 2. If the concentration doubles, the reaction rate increases by a factor of 4.
The overall order of a reaction is the sum of the orders of each reactant. The page also introduces the concept of initial rate and provides concentration-time graphs for different reaction orders.
Highlight: For first-order reactions, the time for the concentration to halve is constant.
The rate constant for a first-order reaction can be calculated from the half-life using the equation:
Example: K = ln / t½
The page concludes with concentration-time graphs for zero, first, and second-order reactions, illustrating how the reaction rate changes over time for each order.
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Samantha Klich
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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
How Concentration and Temperature Affect Reaction Rates for Kids
Gracey
@gracey_irtg
A comprehensive guide to reaction rates and kinetics, covering key concepts in physical chemistry. This summary explores how concentration affects reaction rate, understanding first and second order reactions, the rate determining step, and the Arrhenius equation.... Show more
Rate-Concentration Graphs and Advanced Concepts
This page expands on rate-concentration graphs for different reaction orders and introduces more advanced concepts in chemical kinetics.
For zero-order reactions, the rate-concentration graph is a horizontal line, as the rate is constant regardless of concentration. The rate equation for a zero-order reaction is:
Example: rate = k⁰ = k
For first-order reactions, the rate-concentration graph is a straight line passing through the origin, with the gradient equal to the rate constant k. The rate equation for a first-order reaction is:
Example: rate = k¹
Second-order reactions have a more complex rate-concentration relationship, and the rate constant cannot be directly determined from the graph. The rate equation for a second-order reaction is:
Example: rate = k²
The page then introduces the concept of clock reactions, where the time from the start to a visual change is measured and assumed to represent the initial rate.
Definition: Rate Determining Step: The slowest step in a reaction mechanism, which determines the overall reaction rate.
The rate equation only includes reacting species involved in the rate-determining step.
The Arrhenius equation is introduced, relating reaction rate to temperature and activation energy:
Example: ln k = -Ea/RT + ln A
Where:
- k is the rate constant
- Ea is the activation energy
- R is the gas constant
- T is the temperature
- A is the pre-exponential factor
Highlight: The Arrhenius equation takes into account the frequency of collisions with the correct orientation and represents the proportion of molecules that exceed the activation energy and have sufficient energy for a reaction to take place.
The page concludes by showing how to determine the activation energy from an Arrhenius plot, where the gradient is equal to -Ea/R.
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Access to all documents
Improve your grades
Join milions of students
By signing up you accept Terms of Service and Privacy Policy
Rates of Reaction
This page introduces the concept of reaction rates and explores different reaction orders. It explains how concentration affects reaction rate for zero, first, and second-order reactions.
The rate of a reaction is defined as the quantity reacted or produced over time, or the change in concentration over time. The page then delves into the characteristics of different reaction orders:
Definition: Zero-order reaction: The concentration of the reactant has no effect on the rate.
Definition: First-order reaction: The rate depends on the reactant concentration to the power of 1. If the concentration doubles, the reaction rate increases by a factor of 2.
Definition: Second-order reaction: The rate depends on the concentration raised to the power of 2. If the concentration doubles, the reaction rate increases by a factor of 4.
The overall order of a reaction is the sum of the orders of each reactant. The page also introduces the concept of initial rate and provides concentration-time graphs for different reaction orders.
Highlight: For first-order reactions, the time for the concentration to halve is constant.
The rate constant for a first-order reaction can be calculated from the half-life using the equation:
Example: K = ln / t½
The page concludes with concentration-time graphs for zero, first, and second-order reactions, illustrating how the reaction rate changes over time for each order.
We thought you’d never ask...
What is the Knowunity AI companion?
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.
Where can I download the Knowunity app?
You can download the app from Google Play Store and Apple App Store.
Is Knowunity really free of charge?
That's right! Enjoy free access to study content, connect with fellow students, and get instant help – all at your fingertips.
Can't find what you're looking for? Explore other subjects.
Students love us — and so will you.
4.9/5
App Store
4.8/5
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