Final answer:
The reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH) is exothermic with an enthalpy change of -56 kJ per mole. This is indicated by the increase in temperature during the reaction, which shows that energy is released to the surroundings.
Step-by-step explanation:
The question is asking about the energy change for the reaction between hydrochloric acid (HCl) and sodium hydroxide (NaOH) when they react in an aqueous solution. This reaction is represented by the equation: NaOH (aq) + HCl(aq) → NaCl(aq) + H2O(l).
From the given information, we can deduce that the reaction is exothermic because the temperature increases when the substances react. In an experimental setup with 0.0500 mol of HCl reacting with 0.0500 mol of NaOH, producing 2.9 kJ of heat, we can scale this up to a standard enthalpy change (ΔH) for one mole of reactants by multiplying by 20 (since 0.0500 mol is 1/20th of a mole), which gives us an enthalpy change of -56 kJ/mol (as stated in the provided background information). This indicates that the reaction releases energy in the form of heat to the surroundings and the enthalpy change for the reaction is -56 kJ per mole, which can be described as exothermic.