In the forward direction, how does the energy absorbed in bond making compare with the energy released in bond making?
In the forward direction of a chemical reaction, the energy absorbed in bond making is generally greater than the energy released in bond making. This is because breaking existing bonds in the reactant molecules requires an input of energy, while forming new bonds in the product molecules releases energy.
In the forward direction, the energy absorbed in bond breaking is equal to the energy released in bond making. This is known as the principle of conservation of energy. According to this principle, energy cannot be created or destroyed, it can only be transferred or converted from one form to another. In a chemical reaction, the breaking of bonds requires energy input, which is absorbed from the surroundings. Conversely, the formation of new bonds releases energy into the surroundings. Thus, the energy absorbed in bond breaking is equal to the energy released in bond making, resulting in a balanced energy transfer in the forward direction of a chemical reaction.
To determine how the energy absorbed in bond breaking compares with the energy released in bond making, you need to consider the concept of bond energies.
Bond energy, also known as bond dissociation energy, is the amount of energy required to break a chemical bond. This energy can be absorbed in the form of heat or light. Conversely, when a bond is formed, a certain amount of energy is released.
To find the difference in energy absorbed and released during bond breaking and bond making, you can follow these steps:
1. Identify the chemical reaction of interest. For example, let's consider the reaction of hydrogen (H2) combining with oxygen (O2) to form water (H2O): 2H2 + O2 → 2H2O
2. Determine the specific bonds broken and formed during the reaction. In this case, you have four H-H bonds breaking in the hydrogen gas molecules (H2) and one O=O bond breaking in the oxygen gas molecule (O2). Simultaneously, you have four new O-H bonds forming in the water molecules (H2O).
3. Look up the bond energies (in kilojoules per mole, kJ/mol) of the bonds involved. Bond energy values can be found in reference books, databases, or various online sources.
4. Calculate the total energy absorbed in bond breaking and the total energy released in bond making. Multiply the number of bonds broken or formed by their respective bond energy values and sum them up.
For the example reaction, let's assume the following approximate bond energy values:
- H-H bond energy: 436 kJ/mol
- O=O bond energy: 498 kJ/mol
- O-H bond energy: 464 kJ/mol
The energy absorbed in bond breaking can be calculated as:
Energy absorbed = (energy required to break 4 H-H bonds) + (energy required to break 1 O=O bond)
= (4 * 436 kJ/mol) + (1 * 498 kJ/mol)
The energy released in bond making can be calculated as:
Energy released = (energy released when forming 4 O-H bonds)
= (4 * 464 kJ/mol)
By comparing the values of energy absorbed and released, you can determine the net energy change in the reaction (whether it is exothermic or endothermic) and how the energy absorbed in bond breaking compares to the energy released in bond making.