Physical changes that involve liquids and aqueous solutions can be studied using a polystyrene calorimeter like the one shown in Figure 1. Such materials can be applied to practical thermochemical systems. For example, when athletes are injured, they may immediately hold an ‘instant cold pack’ against the injury; and over time, the athlete may apply ‘instant hot pack’ to help recover. The medical hot/cold pack operates on the principle that certain salts dissolve endothermically in water, while others dissolve exothermically. The amount of heat per unit mass involved in the dissolving of a compound is a characteristic property of that substance. It is called the enthalpy of solution. The purpose of this experiment is to use calorimetry to determine the enthalpy of solution of an unknown salt, and then to use that value to identify the salt in a medical hot/cold pack, from a list of possible candidates.
Categories: Lab/Student Activity
The students will be improving the design of an old house/mall/school/castle by designing and constructing a device that will allow accessibility from one floor to the other so that it fulfills the... read more
Written by Amanda Choi, Don Galbraith Award Winner, 2019-20, Ontario Institute for Studies in Education In this lesson, students will learn to distinguish characteristics of animals within the... read more
Over-arching Inquiry: How can an understanding of Mechanical Advantage and Mechanical Efficiency help to create a useful application for everyday life? (teacher note: you can always have students... read more