Our second project this semester was to create a safe, effective, good looking, inexpensive hand warmer to be sold. With outdoor sporting events in mind, we were tasked with developing such a hand warmer using chemistry. Concepts:Heat
Heat is the energy transferred between samples of matter due to a temperature differential.
q=mcΔt
This equation relates energy lost or gained in a reaction to the mass, specific heat and temperature change of a given system.
Endothermic Reactions
An endothermic reaction is one in which the system gains energy in the form of heat. Simply, the heat of the products is greater than that of the reactants.
Exothermic Reactions
Conversely, an exothermic reaction is one in which the system loses energy in the form of heat. Simply, the heat of the products is less than that of the reactants.
Calorimeter
A calorimeter is a device used to measure the heat within a chemical reaction. In our lab, we used a coffee cup and a thermometer to act as a calorimeter to observe temperature changes of various reactions.
Specific Heat
An object's specific heat capacity is its ability to retain heat. It is defined as the required heat to raise a given mass of a substance by a certain degree amount
The Calcium Chloride and water dissociate together. The water breaks down the calcium chloride into separate ions. The Calcium ions and Oxygen ions bind together and the Chlorine ions and Hydrogen ions also bind together. When the Oxygen and Calcium ions bond and the Hydrogen and Chlorine ions bond the reaction gives off heat by the way of an exothermic reaction. When the water breaks down the salt, the reaction absorbs heat, which means the reaction is endothermic. When the bonds release energy (in the form of heat), the hand warmer takes effect and warms those hands.
Reflection:
This project was very time consuming in our second semester. It was a lot of work, and made me think outside of the box. My group I had worked very well together. One member of our group would do the calculations, one would do the design, and one would make the design. I was in charge of making the design. We used a heat press and plastic bags to make the hand warmer. I had to make the design multiple times and made sure it would work when we presented it. This was one of the hardest projects this year, and I think our group executed it very well.