Rec5a_f04 - Recitation Activity 5 (Chem 121) Chapter 5 1....

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1 Recitation Activity 5 (Chem 121) Chapter 5 1. If you went to a football game with a thermos of tea and a thermos containing the same mass of potato soup, heated to the same initial temperature, which would cool faster and why? Nearly everything in a condensed phase has a heat capacity less than water. (Hint#1: The potato soup has a large proportion of starch and fat which have much lower specific heats than that of water. Hint#2: The greater the heat capacity of a substance, the greater the heat required to produce a given rise in temperature. The heat capacity for 1 gram of a substance is called the specific heat (C s ). C s = q/(m x ?T)) [ONLY SPEND A MAXIMUM OF 10 MINUTES ON THIS PROBLEM] In the same period of time, potato soup gets cold, and gelatinous, while tea stays toasty warm. It is a matter of how heat (thermal energy) is transferred from the system to the surroundings. It is reasonable to assume that both thermos’ lose heat at the same rate so q(soup) = q(tea). Since the mass of the tea and the soup are the same it comes down to the specific heat. According to the following equation: q = C s x m x ? T Since the tea has a much higher specific heat it will have a lower T and the temperature will decrease more slowly as it loses heat. 2. Sodium chlorite is used in some bleaching agents due to its ability to oxidize organic compounds. Write a balanced equation to represent the oxidation-reduction reaction for the reaction between sodium chlorite and glucose (C 6 H 12 O 6 ) to form sodium chloride, carbon dioxide and liquid water. Use the standard enthalpies of formation (found in your book) to calculate the enthalpy of this reaction. Is it exothermic or endothermic?
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This note was uploaded on 07/17/2008 for the course CHEM 121 taught by Professor Wyzlouzil during the Fall '07 term at Ohio State.

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Rec5a_f04 - Recitation Activity 5 (Chem 121) Chapter 5 1....

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