Question

If you perform an experiment where 5.622 grams HCl reacts completely with NaOH, what will be the heat flow that occurs? The DHrxn of HCl and NaOH neutralization is -56.0 kJ/mol. (Hint: put a negative sign on the answer to reflect heat transfer from the system to the surroundings; put no sign on the answer to reflect heat transfer from the surroundings to the system.)

Answer 1

To find the heat flow when 5.622 grams of HCl reacts with NaOH, convert the mass to moles and multiply by the enthalpy change of -56.0 kJ/mol. The total heat flow is -8.630 kJ, indicating an exothermic reaction.

Step-by-step explanation:

To determine the heat flow when 5.622 grams of HCl reacts completely with NaOH at the given enthalpy change (ΔHrxn) of -56.0 kJ/mol for the neutralization reaction, we must first convert the mass of HCl to moles. For HCl, which has a molar mass of approximately 36.46 g/mol, the moles of HCl are calculated as 5.622 grams / 36.46 g/mol, which is approximately 0.1541 mol. Given that the enthalpy change is -56.0 kJ/mol, the total heat flow (q) for the reaction is -56.0 kJ/mol multiplied by the moles of HCl, which equals -8.630 kJ.

The negative sign indicates that heat is released from the system to the surroundings, making it an exothermic reaction.