A student dissolves 14.8 g of ammonium nitrate (NH4NO2) in 300. g of water in a well-insulated open cup. He then observes the temperature of the water fall from 20.0°C to 15.0°C over the course of 4.3 minutes. Use this data, and any information you need from the ALEKS Data resource, to answer the questions below about this reaction: NH4NO3(s) → NH4+(aq) + NO3^- (aq)

Required:
a. Is this reaction exothermic, endothermic, or neither?
b. If you said the reaction was exothermic or endothermic, calculate the amount of heat that was released or absorbed by the reaction in this case.