Question

The standard enthalpy of formation of NO(g) is +90.3 kJ·mol-1 and that of NO2(g) is +33.2 kJ·mol-1. Calculate the reaction enthalpy for 2NO(g) + O2(g) ® 2NO2(g) A. -47.8 kJ B. -57.1 kJ C. +123.5 kJ D. -23.9 kJ E. -114.2 kJ Please explain why/steps.

Answer 1

Page No.: The standard enthalpy of formation of Nog) is given as 90.3 kJ/mot! formation of No cgs is - IN₂ (g) + + O2 (g) No (g) - AH NO = 90.3 Kb hol Sinifarly, the standard enthalpy of formation of No, (gn is 33.2 KI mo! formation reaction of NO₂ (g) is - I N₂ cas + O₂ (9) NO₂ (9) @ Blator = 33.2kJ mol le Now, we need given reaction the reaction which is enthalpy as follows for the QNO₂ (g) + O2(g) 2 NO₂ (g)

Date: 1 To get Lo get the this and desired through reaction we need to the reactions of In and reaction reverse it - multiply it by a like 2011 Ne 17) + $02 (9))— AX(No egy) mol N2 (8) + O₂ (g) → 2 NO(g) AM = 290.3 KI SH = 180.6 kJ Wohlille sexes when we reverse this reaction the sign for this reactions formation enthaltpy also change. 2 NO(g) → O2cg) + N2 (9) SH= -1806 КТ Similarly by 2 reverse in and it) reaction keep @ it multiply this reaction same (means don't - N2(g) +20₂ (g) 2 NO₂ lg D'H= 66.4 KT

Page No.: Date: / / Add the 0 and reactions 0 - which are the outcomes of 2 No (g) Nzeg - O2(g) + NO (1 +20₂ → 2 NO2(g) AH = - 180.6 kJ DH = 66.6 kJ A H=-114.2 kJ 2 NO (g) + O2 egg → 2NO 2 (g) Enthalpy for reaction given is AH = - 114.2 KJ/ Option (E) is correct.