When 1 mole of hydrogen interacts with 1 mole of chlorine, 185 kJ of heat was released.

When 1 mole of hydrogen interacts with 1 mole of chlorine, 185 kJ of heat was released. Find the heat of formation of hydrogen chloride.

Given:
n (H2) = 1 mol
n (Cl2) = 1 mol
Q1 = 185 kJ

To find:
Q -?

1) Write the equation of the thermochemical reaction:
H2 + Cl2 => 2HCl + 185 kJ;
2) As a result of the interaction of 1 mol of hydrogen and 1 mol of chlorine, 2 mol of hydrogen chloride are formed. To calculate how much heat will be released during the formation of 1 mole of hydrogen chloride, it is necessary to make a proportion and solve it:
2 mol HCl – 185 kJ;
1 mol HCl – Q kJ;
Q = 1 * 185/2 = 92.5 kJ.

Answer: The amount of heat is 92.5 kJ / mol.