Answer: 53 kJ/mol
Explanation:
Hello, for the chemical reaction you're asking, consider that its balance result:
[tex]H_2+I_2-->2HI[/tex]
Now, the energy change is given by the difference in the standard enthalpy of formations times the stoichiometric coefficient in the chemical reaction:
[tex]H_{rxn}^0=H_{f,HI}^0*2-H_{f,H_2}^0-H_{f,I_2}^0[/tex]
Since hydrogen and iodine are gases, their enthalpy of formation is 0 and the hydrogen iodide has a value of 26.5 kJ/moL, thus, the energy change at standard conditions is given by:
[tex]H_{rxn}^0=26.5 kJ/mol*2\\H_{rxn}^0=53 kJ/mol[/tex]
Best regards.
