Use the bond enthalpies and bond energies from the data book in themochemical equations to calculate the reaction enthalpy of:H2(g) + Br2(g) ->2HBr(g) and show your workings in the question above in an energy level diagram.please..
To calculate the reaction enthalpy using bond enthalpies, we need to understand the concept of bond enthalpy. Bond enthalpy (also known as bond energy) is the amount of energy required to break a chemical bond in a compound.
Using bond enthalpies, we can determine the energy required to break the bonds in the reactants and the energy released when new bonds are formed in the products. The difference between these energies gives us the overall energy change, also known as the reaction enthalpy.
Let's break down the reaction:
H2(g) + Br2(g) -> 2HBr(g)
First, we need to determine the bonds involved in the reactants and the products, along with their respective bond energies or bond enthalpies.
The bond enthalpies are typically given in kilojoules per mole (kJ/mol) and can be found in a data book or reference source.
1. Breaking the bonds in the reactants:
In H2(g), there is one H-H bond. The average bond enthalpy for an H-H bond is approximately 436 kJ/mol.
In Br2(g), there is one Br-Br bond. The average bond enthalpy for a Br-Br bond is approximately 193 kJ/mol.
To break these bonds, we need to supply energy equal to the sum of the bond enthalpies:
Energy required to break H-H bond = 1 * 436 kJ/mol = 436 kJ/mol
Energy required to break Br-Br bond = 1 * 193 kJ/mol = 193 kJ/mol
2. Forming the bonds in the products:
In 2HBr(g), there are two H-Br bonds. The average bond enthalpy for an H-Br bond is approximately 365 kJ/mol.
To form these bonds, energy is released. The total energy released is equal to the sum of the bond enthalpies:
Energy released by forming 2 H-Br bonds = 2 * 365 kJ/mol = 730 kJ/mol
3. Calculating the reaction enthalpy:
To obtain the reaction enthalpy, we subtract the energy required to break the bonds (reactants) from the energy released by forming the bonds (products):
Reaction enthalpy = Energy released - Energy required
Reaction enthalpy = (730 kJ/mol) - (436 kJ/mol + 193 kJ/mol)
Reaction enthalpy = 730 kJ/mol - 629 kJ/mol
Reaction enthalpy = 101 kJ/mol
This indicates that the reaction is exothermic, releasing 101 kJ of energy per mole of reaction.
An energy level diagram visually represents the energy changes during a chemical reaction. Unfortunately, I am limited to text, so I cannot provide a visual energy level diagram. However, you can draw an energy level diagram by plotting the energy of the reactants and products on the y-axis, and the progress of the reaction (from reactants to products) on the x-axis. The difference in energy between the reactants and products will give you the reaction enthalpy.
I hope this explanation has been helpful! If you have any further questions, feel free to ask.