Hand Warmer Challenge
For this project, we were given the task to design and create a hand warmer that efficiently increases in temperature by roughly 20°C, has a volume of about 50mL, profitable, and uses safe chemicals that we have worked with in previous labs. The goal in creating these hand warmers is to have them available for purchase in our San Marin Student Store for students and their parents, in particular during outside sporting events due to the cold temperatures in the winter, or wearing them at school during break or lunch. The process our group went through was to first discover a successful product and then refine our design to appeal to those who will be buying our hand warmers.
Key Chemistry Concepts:
- Thermochemistry - the study of the transfers of energy as heat that accompany chemical reactions and physical changes
- Intermolecular Forces - break bonds and particulate attractions that absorb energy from the surroundings
- Interparticle Forces - form new bonds and particulate attractions that release energy from the surroundings
- Law of Conservation - energy cannot be created or destroyed, only changed from one form to another or transferred from one system to another
- Ionic Solids - are solids composed of oppositely charged ions. They consist of positively charged cations and negatively charged anions
- Exothermic Reactions - a chemical reaction that releases energy
- Endothermic Reactions - reaction in which the system absorbs energy from its surroundings
- Specific Heat - the amount of energy required to raise the temperature of one gram of a substance by 1°C or 1K
- Calorimetry - measurement of the amount of heat released or absorbed in a chemical reaction, change of state, or formation of a solution. We used calorimetry in our first lab where we measured the amount of time the cooling process was for our hand warmer. This involved the use of a calorimeter, which is a container that determines the enthalpy change that occurs during a process
- Enthalpy of Formation - the amount of energy released or absorbed during a reaction in which a substance is produced. The amount of energy released in our reaction was 532.20 Joules
- Entropy - a measure of the randomness or disorder of a system for our hand warmer there is an increase in entropy because as energy is added, the randomness of the molecular motion increases.
Reflection:
Overall, this project was very a very fun way to learn about the new chemistry concepts, as well as integrating them into our project. Just like any other good project there were many pits and peaks throughout its process. We began as a group by brainstorming all of our ideas we had for the hand warmer and eventually combined them. One of the best peaks of this project was how well our group worked together and combined all of our ideas. This made it so that we could work very efficiently and effectively. Another strong peak we had was how well we managed our time and completed every task we needed to have completed. For example, we would set ourselves deadlines to have certain aspects of our project completed and we would get it done by that deadline. A pit that we had was when there were no mini baggies left and they were a huge element to our hand warmer as they were what held and released the lithium chloride. This was a little step back but we were able to work around it as we created our own mini bags, which seemed to work just as well. Another pit that we had was that during the day of our presentation, somebody had thrown away all of our prototypes so we did not have our physical hand warmer with us. We were able to manage through it and still give the class a thorough understanding of exactly how our hand warmer works. Throughout this project, I learned about multiple new concepts and gained new life skills as well. I learned about various formulas for common ions, and how to solve problems involving specific heat, change in temperature, and enthalpies of reactions. Some cool skills that I learned throughout this project were how to work with different chemicals safely and how to use a heat sealer to close materials without any gaps.
Overall, this project was very a very fun way to learn about the new chemistry concepts, as well as integrating them into our project. Just like any other good project there were many pits and peaks throughout its process. We began as a group by brainstorming all of our ideas we had for the hand warmer and eventually combined them. One of the best peaks of this project was how well our group worked together and combined all of our ideas. This made it so that we could work very efficiently and effectively. Another strong peak we had was how well we managed our time and completed every task we needed to have completed. For example, we would set ourselves deadlines to have certain aspects of our project completed and we would get it done by that deadline. A pit that we had was when there were no mini baggies left and they were a huge element to our hand warmer as they were what held and released the lithium chloride. This was a little step back but we were able to work around it as we created our own mini bags, which seemed to work just as well. Another pit that we had was that during the day of our presentation, somebody had thrown away all of our prototypes so we did not have our physical hand warmer with us. We were able to manage through it and still give the class a thorough understanding of exactly how our hand warmer works. Throughout this project, I learned about multiple new concepts and gained new life skills as well. I learned about various formulas for common ions, and how to solve problems involving specific heat, change in temperature, and enthalpies of reactions. Some cool skills that I learned throughout this project were how to work with different chemicals safely and how to use a heat sealer to close materials without any gaps.