In this question, we have a neutralization reaction occurring and giving a value of heat, the informations we have are:
HCl = 50.0 mL and 1.0 M
NaOH = 75.0 mL and 1.0 M
ΔT = 20.2 - 25.6 = -5.4°C
We will be using the calorimetry formula in this situation, adding the values of the quantity of both reactants and using the specific heat capacity of water, c = 4.19J, the formula is:
Q = mcΔT
We have:
m = 50+75
c = 4.19J
ΔT = - 5.4
Now we add these values into the formula:
Q = 125 * 4.19 * - 5.4
Q = -2.83 kJ, this is the overall enthalpy, or energy transferred, and the minus sign in front of the number indicates that this is an exothermic reaction.
