Endothermic Reaction - Temperature is Measured Still Images An electronic thermometer is used to determine that the reactants in this experiment are at room temperature. Ammonium thiocyanate is mixed with barium hydroxide. The mixture is stirred and the two solids react. A slush is formed because water is one of the products of the reaction. After the reaction, the temperature is again measured. The reaction is endothermic, that is, it takes in heat. The temperature is now negative 25 degrees Celsius. (When the temperature is measured it has dropped to between negative 20 and negative 30 degrees Celsius so the temperature is well below the freezing point of water. The equation for the reaction shows that barium thiocyanate, ammonia gas and water are formed by the reaction of the solid barium hydroxide and the solid ammonium thiocyanate.) You can get at large JPEG versions of the images by means of the following links. 10 11 12 13 14 15 16 17 Back to the topic
An electronic thermometer is used to determine that the reactants in this experiment are at room temperature. Ammonium thiocyanate is mixed with barium hydroxide. The mixture is stirred and the two solids react. A slush is formed because water is one of the products of the reaction. After the reaction, the temperature is again measured. The reaction is endothermic, that is, it takes in heat. The temperature is now negative 25 degrees Celsius. (When the temperature is measured it has dropped to between negative 20 and negative 30 degrees Celsius so the temperature is well below the freezing point of water. The equation for the reaction shows that barium thiocyanate, ammonia gas and water are formed by the reaction of the solid barium hydroxide and the solid ammonium thiocyanate.)
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© 1999 Division of Chemical Education, Inc., American Chemical Society. All rights reserved.
