Experiments In General Chemistry 22

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Purpose: Establish which salt solution would prove to be the most cost effective for the company to produce hot and cold packs that reach temperatures of 65° C and 0° C, respectively, as well as their relevant prices of production. Introduction: The Dystan Medical Supply Company is searching for a salt solution for their hot and cold packs that will be most cost effective. The cost of production per pack must be less than $5.00 for the company to make a profit. Four salts: ammonium nitrate, calcium chloride, lithium chloride, and potassium chloride will be tested to find to most cost effective solution. The salts will be dissolved in distilled water by small quantities until the reaction reaches When ionic compounds dissolve in water, they either absorb energy from or release energy to the surroundings. If a chemical reaction absorbs heat from the surroundings, it is an endothermic reaction. If a solution releases heat to its surroundings, it is an exothermic reaction. The enthalpy of dissolution is the enthalpy change associated with the dissolution of a substance in a solvent at a constant pressure. The change in enthalpy relies on the concentration of the salt solution, because different concentrations will produce different enthalpies. There is an equation to determine how much of this heat energy is lost or gained when a reaction is performed. Q = c m (T1-T2) Where: q is the energy in Joules C is the heat capacity, measured in joules per gram per degree Celsius M is the mass of the solution, measured in grams J is the joules G is the grams of water T is the temperature ΔH=ΔE + PΔV = (q p +w) – w = q p Procedure: 1. Follow instructions 1-9 in Appendix A-1 to initialize the MeasureNet workstation. a. Turn on the MeasureNet workstation. b. Press Main Menu, then press F2 Temperature, then F1 Temperature vs. Time. c.

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