Final answer:
The enthalpy change of a reaction is a measure of the heat energy transferred during the reaction. In this case, the reaction 2H₂ + O₂ → 2H₂O has an enthalpy change of -484 kJ. When 1.70 mol of H₂ reacts, the transfer of heat is 823 kJ released. The correct option is A.
Step-by-step explanation:
The enthalpy change of a reaction is a measure of the heat energy transferred during the reaction. In this case, the reaction is 2H₂ + O₂ → 2H₂O and the enthalpy change is ΔH-rxn = -484 kJ. To determine the transfer of heat when 1.70 mol of H₂ reacts, we need to calculate the amount of heat released or absorbed.
First, we need to determine the moles of H₂O produced. Since the reaction is 2H₂ + O₂ → 2H₂O, for every 2 moles of H₂ reacted, 2 moles of H₂O are produced. Therefore, if 1.70 mol of H₂ reacts, we can expect the production of 1.70 mol/2 = 0.85 mol of H₂O.
The enthalpy change is given per mole of reaction, so we can calculate the amount of heat transferred by multiplying the enthalpy change by the number of moles of reaction. In this case, the heat transfer for 0.85 mol of H₂O can be calculated as follows: (0.85 mol) * (-484 kJ/2 mol) = -205.4 kJ.
Since the enthalpy change is negative, the reaction releases heat. Therefore, the answer is A. 823 kJ released.