3. Lightsticks contain a substance that breaks down during a chemical reaction. A release of energy (as light) accompanies this reaction. Therefore, the amount of light released is proportional to the number of molecules breaking down. a) The lightsticks below are in water of different temperatures. Which one is in the warmer water? b) What would be the effect on the intensity of a lightstick and the duration of its glow if a lightstick was placed in a freezer?
Thermochemistry
Thermochemistry can be considered as a branch of thermodynamics that deals with the connections between warmth, work, and various types of energy, formed because of different synthetic and actual cycles. Thermochemistry describes the energy changes that occur as a result of reactions or chemical changes in a substance.
Exergonic Reaction
The term exergonic is derived from the Greek word in which ‘ergon’ means work and exergonic means ‘work outside’. Exergonic reactions releases work energy. Exergonic reactions are different from exothermic reactions, the one that releases only heat energy during the course of the reaction. So, exothermic reaction is one type of exergonic reaction. Exergonic reaction releases work energy in different forms like heat, light or sound. For example, a glow stick releases light making that an exergonic reaction and not an exothermic reaction since no heat is released. Even endothermic reactions at very high temperature are exergonic.
![### Educational Content on Lightsticks
3. **Lightsticks and Chemical Reactions**
Lightsticks contain a substance that breaks down during a chemical reaction. A release of energy (as light) accompanies this reaction. Therefore, the amount of light released is proportional to the number of molecules breaking down.
**a) Temperature and Light Intensity**
The image shows two lightsticks submerged in beakers of water at different temperatures. One lightstick glows more brightly than the other. The brighter lightstick is in the warmer water. In warmer conditions, the reaction rate increases, resulting in more light being emitted due to faster molecular breakdown.
**b) Effect of Freezing on Lightsticks**
What would be the effect on the intensity of a lightstick and the duration of its glow if a lightstick was placed in a freezer?
Placing a lightstick in a freezer would decrease its intensity because the chemical reaction slows down in colder temperatures. However, the duration of its glow would be extended since the reaction progresses more slowly, using up the reactants over a longer period.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F8796f270-f66d-4e05-adbc-919a3794eb0d%2Ff7c8a706-b790-4c09-8e0e-68cb9596b7e6%2Fm3h86ep_processed.png&w=3840&q=75)
![](/static/compass_v2/shared-icons/check-mark.png)
Trending now
This is a popular solution!
Step by step
Solved in 2 steps
![Blurred answer](/static/compass_v2/solution-images/blurred-answer.jpg)
![Chemistry](https://www.bartleby.com/isbn_cover_images/9781305957404/9781305957404_smallCoverImage.gif)
![Chemistry](https://www.bartleby.com/isbn_cover_images/9781259911156/9781259911156_smallCoverImage.gif)
![Principles of Instrumental Analysis](https://www.bartleby.com/isbn_cover_images/9781305577213/9781305577213_smallCoverImage.gif)
![Chemistry](https://www.bartleby.com/isbn_cover_images/9781305957404/9781305957404_smallCoverImage.gif)
![Chemistry](https://www.bartleby.com/isbn_cover_images/9781259911156/9781259911156_smallCoverImage.gif)
![Principles of Instrumental Analysis](https://www.bartleby.com/isbn_cover_images/9781305577213/9781305577213_smallCoverImage.gif)
![Organic Chemistry](https://www.bartleby.com/isbn_cover_images/9780078021558/9780078021558_smallCoverImage.gif)
![Chemistry: Principles and Reactions](https://www.bartleby.com/isbn_cover_images/9781305079373/9781305079373_smallCoverImage.gif)
![Elementary Principles of Chemical Processes, Bind…](https://www.bartleby.com/isbn_cover_images/9781118431221/9781118431221_smallCoverImage.gif)