Question

The standard heat of formation of no2 and n2o4 are 8and 4 kcal/ mol respectively the heat of dimeris
ation of no2 in kcal is

Answer 1

The heat of dimeris ation of NO₂ is - 12 kcal/mol

Explanation:

The heat of dimerisation is heat produced when formation of reactants and products.

The product and the reactant involved in the formation of nitrogen dioxide is NO₂ and N₂O₄

From question, the heat produced during formation of NO₂ is:

H_NO₂ = 8 kcal/mol

From question, the heat produced during formation of N₂O₄ is:

H_N₂O₄ = 4 kcal/mol

Now, the heat dimerisation is:

Hd = H_N₂O₄ - (2 × H_NO₂)

Hd = 4 - (2 × 8)

Hd = 4 - 16

∴ Hd = -12 kcal/mol