3) The rocket fuel hydrazine, has the formula N2Ha(). This is combined with oxygen gas to form nitrogen gas and water vapour. (Use bond energies from the Table (see Content)) (5 Marks) a Draw the structural formula for all the species involved in the reaction. b Write a balanced chemical equation for the reaction. C) Determine the enthalpy change (kJ/mol) when 1 mole of hydrazine reacts using bond energies. 4. Present your solution to Question #3 in a fully labeled Bond Energy Diagram. Clearly indicate whether the reaction is endothermic or exothermic. (5 Marks)

Balanced reaction:

N₂H₄ + O₂ -> N₂ + 2H₂O

Enthalpy change

?H = -2571kJ/mol

The reaction is exothermic since ?H is negative.

Step-by-step explanation

Identify the reactants and products then get the balanced reaction equation. N2H4 and O2 are the reactants and N2 and H2O are products. Balance the equation so that the number of atoms of each element on both sides of the chemical equation is equal.

N₂H₄ + O₂ -> N₂ + 2H₂O

Draw the structure of each species by using the knowledge of Lewis structure. See attached figure for the structures.

Using the bond energies, get the enthalpy change.

?H = sum of bonds broken - sum of bonds formed

Identify the bonds broken in the reactant side. First, N2H4 has 1 N-N bond and 4 N-H bonds. Second, O2 has 1 O=O bond. So the sum of bonds broken is:

Sum of bonds broken = 1 N-N + 4 N-H + 1 O=O

Use the table for values

Sum of broken bonds = 163 + 4(391) + 495 = 222kJ/mol

Next, for the bonds formed, N2 has 1 N-triplebond-N, and H2O has 2 O-H bonds. However, in the given chemical reaction, there are 2mol of H2O per 1 mol of N2H4, so we need to multiply the bond energy of H2O by 2.

Sum of bonds formed = 1 N-triplebond-N + 2(2 O-H)

Use the table again

Sum of bonds formed = 941 + 2(2*463) = 2,793 kJ/mol

Get the change in enthalpy

?H = sum of bonds broken - sum of bonds formed

?H = 222kJ/mol - 2793kJ/mol = -2571kJ/mol

Since ?H is negative, the reaction is exothermic.

Please see the attached file for the complete solution