Each of eleven unidentified compounds is heated in a test tube to determine whether the endothermic change each undergoes is a chemical change or a physical change. A chemical change is identified on the basis of a change in visible properties (physical state and color) of any material that remains after heating. A physical change is identified on the basis of appearance during heating (formation of liquid or gas) and a return to the original physical state and color on cooling, either in the bottom of the test tube or as a condensate or deposit on the cooler upper portion of the tube.
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Instructions for the students and notes for the instructor are available.
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