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Heat of Reactions Problems
There’s a few ways that Heat of Reactions problems can be phrased:
1. Is the reaction endothermic or exothermic?
What type of reaction is CH4 + 2O2 CO2 + 2H2O ?
Find this equation on Reffy, Table I (p.5). The ∆H is –890.4 kJ, which means that it’s an
exothermic reaction (see note on bottom of table). 2. Which reaction releases more energy?
Which reaction releases more energy:
CH4 + 2O2 CO2 + 2H2O or C3H8 + 5O2 3CO2 + 4H2O?
Find the ∆H of both reactions. The first reaction’s ∆H is –890.4 kJ and the second reaction’s
∆H is –2219.2 kJ. Since the second ∆H is greater, the second reaction releases more energy. 3. Which reaction absorbs more energy?
We’d answer this question the same way we answered the above question, except we’d be dealing with a positive ∆H instead of a negative ∆H.
UNIT 8: KINETICS AND EQUILIBRIUM © 310
