To calculate the enthalpy change for the precipitation reaction, we first need to determine the balanced chemical equation for the reaction between barium chloride BaCl2 and sodium sulfate Na2SO4 .BaCl2 aq + Na2SO4 aq BaSO4 s + 2NaCl aq Next, we need to determine the amount of heat q released or absorbed during the reaction. Since we are given the heat capacity of the coffee cup calorimeter 10 J/C and the final temperature 25C , we can calculate the heat released or absorbed using the formula:q = C Twhere q is the heat released or absorbed, C is the heat capacity of the calorimeter, and T is the change in temperature.However, we are not given the initial temperature of the solutions. We will assume that the initial temperature of both solutions is also 25C, which means there is no temperature change during the reaction. In this case, T = 0, and the heat released or absorbed q is also 0.q = 10 J/C 0C = 0 JSince there is no heat released or absorbed during the reaction, the enthalpy change H for the precipitation reaction is also 0.H = 0 JTherefore, the enthalpy change for the precipitation reaction of barium chloride and sodium sulfate is 0 J.