Chemistry 30 Thermodynamics: Exothermic and Endothermic Reactions Lab

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Thermodynamics Laboratory

Endothermic and Exothermic Reactions

Overview:
Various salts are dissolved in water in a test tube. Based on temperature changes you can detect by holding the test tubes, determine if the reactions (the dissolving process) are endothermic or exothermic.
Procedure:
Place approximately 25 mL of water in each of two (or more) test tubes. Feel the test tube to get an idea of the water temperature. To each test tube add 2-3 g of a salt. Hold the test tube to determine if the water temperature increased or decreased. Some salts to use: ammonium chloride, NH₄Cl calcium chloride, CaCl₂ potassium nitrate, KNO₃ lithium chloride, LiCl
Questions to Consider
For which salt(s) is the dissolving process endothermic? For which salt(s) is the dissolving process exothermic? How do you know?