Concept explainers
Use the bond energies in Table 5.1 to calculate the energy changes associated with each of these reactions. Label each reaction as endothermic or exothermic.
- a. N2(g) + 3 H2(g) → 2 NH3(g)
- b. H2(g) + Cl2(g) → 2 HCl3(g)
Hint: Draw Lewis structures of the reactants and products to determine the number and kinds of bonds.
(a)
Interpretation:
The energy changes have to be calculated.
Concept introduction:
Endothermic reaction: When the heat energy was absorbed by the system from the surrounding is called endothermic reaction.
Exothermic reaction: When heat energy or light energy was unconfined to the surrounding from the system is called exothermic reaction.
Net energy change is calculated from the difference between the total energy absorbed in breaking bonds and total energy released in forming bonds.
Explanation of Solution
The given reaction is shown below,
Bonds broken in the reactants are given below:
Bonds formed in the products are given below:
The overall energy change is negative, therefore, the reaction is an exothermic reaction.
(b)
Interpretation:
The energy changes have to be calculated.
Concept introduction:
Endothermic reaction: When the heat energy was absorbed by the system from the surrounding is called endothermic reaction
Exothermic reaction: When heat energy or light energy was unconfined to the surrounding from the system is called exothermic reaction.
Net energy change is calculated from the difference between the total energy absorbed in breaking bonds and total energy released in forming bonds.
Explanation of Solution
The given reaction is shown below,
Bonds broken in the reactants are given below:
Bonds formed in the products are given below:
The overall energy change is negative, therefore, the reaction is an exothermic reaction.
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