Which of the following reactions is endothermic?

H2(g) + ½ O2(g)H2O(g),H = -57.82 kcal
½N2(g) + O2(g) + 8.1 kcalNO2(g)
½ N2(g) + 3/2 H2(g)NH3(g) + 11.0 kcal
C(diamond)+ O2(g)CO2,H = -94.50 kcal

Question

Which of the following reactions is endothermic?

H2(g) + ½ O2(g)H2O(g),H = -57.82 kcal
½N2(g) + O2(g) + 8.1 kcalNO2(g)
½ N2(g) + 3/2 H2(g)NH3(g) + 11.0 kcal
C(diamond)+ O2(g)CO2,H = -94.50 kcal

shubhamsrg · Answer

for endothermic, H>0
also if we add energy in the reactant side, then also its endothermic

anonymous · Answer

Can you please explain this a little better, I still don't know which answer it is.

shubhamsrg · Answer

if energy is added , then its an endothermic reaction,
can you tell in which eqns the energy is being added ?

anonymous · Answer

would it be ½ N2(g) + 3/2 H2(g)NH3(g) + 11.0 kcal?

shubhamsrg · Answer

yes, there is one more

anonymous · Answer

½N2(g) + O2(g) + 8.1 kcalNO2(g)?

shubhamsrg · Answer

no wait, 
 ½ N2(g) + 3/2 H2(g)NH3(g) + 11.0 kcal is not endothermic

anonymous · Answer

Ok so is ½N2(g) + O2(g) + 8.1 kcalNO2(g)?

shubhamsrg · Answer

coz energy is added to the product side
if energy is added to the reactant side, then its endothermic

shubhamsrg · Answer

yes,  ½N2(g) + O2(g) + 8.1 kcalNO2(g) is endothermic

anonymous · Answer

Thank you so much!!!