Hi Guys! So I am having problem to assess the concept between the two Problems below:

Problem 1: A 0.500 g sample of TNT (C7H5N2O6) is burned in a bomb calorimeter containing 610 grams of water at an initial temperature of 20.00°C. The heat capacity of the calorimeter is 420 J/°C and the heat of combustion of TNT is 3374 kJ/mol. Using these data, calculate the final temperature of the water and calorimeter once the reaction is complete.

In Problem 1: The formula used is Q_rxn = Q_water + Q_cal, and the answer is 23°C

Problem 2: A 30.14-g stainless steel ball bearing at 117.82°C is placed in a constant-pressure calorimeter containing 120.0 mL of water at 18.44C. If the specific heat of the ball bearing is 0.474 J/g°C, calculate the final temperature of the water. Assume the calorimeter to have negligible heat capacity.

In Problem 2: The formula uses is Q_rxn = - Q_water, and the answer is 21°C

Question is, why did in Problem the formula does not show a negative sign to indicate the direction of heat flow, andd in Problem 2 it does when they are both calorimetry problems and involved solving for the final temperature? Any help is appreciated. Thank you!