Question

In: Chemistry

Use average bond energies to estimate the enthalpy changes of the following reactions: a. N2(g) +...

Use average bond energies to estimate the enthalpy changes of the following reactions: a. N2(g) + 3 H2(g) -> 2 NH3(g) b. N2(g) + 2 H2(g) -> H2NNH2(g) c. 2 N2(g) + O2(g) -> 2 N2O(g)

Expert Solution

Using Bond energy values to calculate enthalpy of rxn:

a) N2 (g) +3H2(g)---->2NH3(g)

Bonds breaking in reactants	bond energy in KJ
NN	1mol*941KJ/mol941KJ
H-H	3mol*(432KJ/mol)1296KJ

bond making in products	bond energy in KJ
N-H	6mol*(391KJ/mol)2346KJ
-	-

enthalpy of rxnenergy required for bond breaking-energy required for bond making(941+1296)-2346-109 KJ

enthalpy change of rxn -109KJ

b) N2 (g) +2H2(g)---->H2NNH2(g)

Bonds breaking in reactants	bond energy in KJ
NN	1mol*941KJ/mol941KJ
H-H	2mol*(432KJ/mol)864KJ

bond making in products	bond energy in KJ
N-H	4mol*(391KJ/mol)1564KJ
N-N	1mol*160KJ/mol160KJ

enthalpy of rxnenergy required for bond breaking-energy required for bond making(941+864)-(1564+160)81 KJ

enthalpy changes of rxn81KJ

c)2N2 (g) +O2(g)---->2N2O(g)

N2O structure:NN-O

Bonds breaking in reactants	bond energy in KJ
NN	2mol*941KJ/mol1882KJ
OO	1mol*(495KJ/mol)495KJ

bond making in products	bond energy in KJ
NN	2mol*941KJ/mol1882KJ
N-O	2mol*201KJ/mol402KJ

enthalpy of rxnenergy required for bond breaking-energy required for bond making(1882+495)-(1882+402) 93KJ

enthalpy changes of rxn93KJ

queen_honey_blossom answered 2 years ago

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