A student runs two experiments with a constant-volume "bomb" calorimeter containing 1000.g of water (see sketch at right). First, a 5.500g tablet of benzoic acid C6H5CO2H is put into the "bomb" and burned completely in an excess of oxygen. (Benzoic acid is known to have a heat of combustion of 26.454kJ/g.) The temperature of the water is observed to rise from 14.00C to 47.07C over a time of 6.4 minutes. Next, 4.560g of acetylene C2H2 are put into the "bomb" and similarly completely burned in an excess of oxygen. This time the temperature of the water rises from 14.00C to 62.00C. Use this information, and any other information you need from the ALEKS Data resource, to answer the questions below about this reaction:

A "bomb" calorimeter.

2C2H2(g) + 5O2(g) 4CO2(g) + 2H2O(g)

Be sure any of your answers that are calculated from measured data are rounded to the correct number of significant digits.

Note for advanced students: it's possible the student did not do these experiments sufficiently carefully, and the values you calculate may not exactly match published values for this reaction.

Is this reaction exothermic, endothermic, or neither?	exothermic
	endothermic
	neither
If you said the reaction was exothermic or endothermic, calculate the amount of heat that was released or absorbed by the reaction in the second experiment.	kJ
Calculate the reaction enthalpy Hrxn per mole of C2H2.	kJ/mol