Question

The standard enthalpy of a reaction, AH, is the energy or enthalpy change associated with transforming reactants into products, where "standard", denoted °, implies reaction conditions of 25°C, 1 atm and/or 1 M. Standard enthalpies of a reaction can be estimated by assuming that all reactant bonds are broken before forming all product bonds: AHTD =( enthalpies of bonds broken) - (2 enthalpies of bonds formed) Using the information below, calculate AH°r (kJ) for the reaction of H2(g) + Cl2(g) 2HC1 (g): H-i: - H-H H-Ci: Bonds broken: H-H and Cl-C Bonds formed: 2 xH-C x 436 mol x 243 mol (2x 431- mol kJ/mol) (2 XkJ/mol) = kJ/mol + (BROKEN BONDS) MINUS (BONDS FORMED Is the net reaction endothermic or exothermic?

Answer 1

Reaction & H₂19) + Qig) → 2HCl (g) In this reaction, H H bond and 2 H-a bondo are and ce-l bond is broken formed. AH = (436 kJ/mol + 243 kJ/mo) -12X431 kJ I mo) ran = - 183 kJ/mol negative The net reaction is sign which means EXOTHERMIC because a Hrxn has that energy is released