Question

If you neutralize 10.0 g of HCl, how many kJ of energy are released?

A) 25 kJ
B) 50 kJ
C) 75 kJ
D) 100 kJ

Answer 1

If you neutralize 10.0 g of HCl, the approximate amount of energy released is -16 kJ.

Step-by-step explanation:

The enthalpy change of the indicated reaction is for exactly 1 mol HCl and 1 mol NaOH; the heat in the example is produced by 0.0500 mol HCl and 0.0500 mol NaOH. So, if 2.9 kJ of heat are produced when 0.0500 mol of HCl is neutralized, then the molar enthalpy change can be calculated as follows:

ΔH = (-2.9 kJ) / (0.0500 mol) = -58 kJ/mol

Therefore, if you neutralize 10.0 g of HCl, which is equal to approximately 0.275 mol of HCl, the amount of energy released will be:

Energy released = ΔH × mol of HCl = (-58 kJ/mol) × (0.275 mol) = -15.95 kJ

Since the energy released is negative, indicating an exothermic reaction, the correct answer is approximately -16 kJ.