Exothermic Reaction

Before conducting the experiment, the online simulation was used to determine which substances were endothermic or exothermic when dissolved in water. According to the simulation, sodium chloride and ammonium chloride was observed to be endothermic. Calcium chloride, sodium acetate, sodium carbonate, and lithium chloride was observed to be exothermic. As sodium chloride and ammonium chloride was observed to be endothermic, those two salt substrates was not used in the experiment as the goal of the experiment was to increase temperature, not decrease it. Additionally, health hazards of the products made by each substrate reacting with water was researched. The 2016 cost per gram of each substrate was given by the instructor. To start the experiment, 10g of sodium acetate, sodium carbonate, calcium chloride, and lithium chloride were weighed out and placed separately into their respective dixie
cup. To measure the amount of heat involved in the chemical reactions of the substrate and water, a calorimeter was made using two styrofoam cups, tape, and stir stick.
One styrofoam cup was cut in half, and the other was cut about ⅓ from the bottom. Then the shorter cut of the two was placed open side facing above and the taller cup was placed on top of the shorter cup to prevent any heat loss to the air. Then the shorter cup was secured on a base with tape and a hole was drilled with a stir stick on the top of the taller cup to allow the stir stick and a thermometer reach the chemical reaction. With the calorimeter set up and ready, the experiment was ready to be conducted. The calorimeter was placed on a metric scale and tared. Then 2.5g of a substrate was measured out using a small scoop and placed in the calorimeter. A scale was used to control the amount of substrate to 2.5g in each trial. Then 20 ml of distilled water was measured using a 50 ml graduated cylinder and the temperature of the distilled water was measured and recorded by placing a thermometer for one
minute. All temperature was recorded in celsius. After recording the temperature of the water, the water was poured on the substrate in the calorimeter and the calorimeter was quickly closed by one of the researchers. After closing the calorimeter, a stir stick was inserted inside the calorimeter and the solution of the substrate and water was stirred for five seconds using a stopwatch to control the amount of heat loss to the stir stick. Then the stir stick was quickly taken out and the thermometer was inserted in the calorimeter. The thermometer was not touched by any researchers to control the heat loss to the thermometer. The thermometer was inserted in the calorimeter for two minutes to let the chemical reactions take place and release heat. After two minutes, the temperature was measured and recorded. With both the initial and resulting temperatures, the change in temperature was calculated and recorded. The calorimeter was then opened up and the solution inside was poured in the waste container, washed, and dried. Both the stir sticks and thermometer was washed and dried. Another two trials were done for the same substrate and repeated for the other substrates. This resulted in each substrate having three trials. After recording all of the necessary data for all four substrates, the equation Q = mCT was used to calculate the heat transfer for each substrate. After gathering the heat transfer for all the substrates, one substrate was chosen to be used to make a hand warmer taking account of the safety, efficiency, and the cost by four researchers. Based on an unanimous vote, one substrate was chosen to be used in a handwarmer based on its safety, efficiency, and the cost.