A 50-mL solution of a dilute AgNO₃ solution is added to 100 mL of a base solution in a coffee-cup calorimeter. As Ag₂O(s) precipitates, the temperature of the solution increases from 23.78 °C to 25.19 °C. Assuming that the mixture has the same specific heat as water and a mass of 150 g, calculate the heat q. Is the precipitation reaction exothermic or endothermic?