CHEM+10H+CHAPTER+10+ICE

WHAT YOU NEED TO KNOW:

How to convert from calories and joules and vice-versa if given the conversion factor Use of the equation H = mc delta T to solve for any of the variables and to determine the final temperature of a mixture of hot and cold liquids and solids (i.e heat lost by the hotter material = heat gained by the cooler material until they reach the same final temperature.) Stoichiometry involving heat, including limiting reactant problems Using Hess's Law to determine the delta H for a reaction given the delta H for its subreactions Definition of endothermic and exothermic Reading the graphs showing the energy of reactants and products in order to determine if a reaction is endothermic or exothermic Using the graphs to label delta H and the activation energy of the reaction. Understanding that when an endothermic reaction occurs, the container holding the reactants gets cold, and that when an exothermic reaction occurs, the container gets hot. Recognizing that delta H is positive for endothermic reactions and negative for exothermic reactions Delta H is like a reactant when the reaction is endothermic and like a product when the reaction is exothermic.

ANSWERS TO THE EXTRA PROBLEMS:

67. (a)190.0 kJ (b) 657.5 cal (c)2.394 x 10^4 cal 68. 7.65 kcal 69. 1627g = 1.6 x 10^3 kg 70. 11 degrees C 71. 0.31 cal/g degree C 72. 3.8 x 10^5 J 73. Gold will undergo the largest change in temperature. Water will undergo the smallest.