Concept explainers
The compound hexaazaisowurtzitane is one of the highest-energy explosives known (C & E News, Jan. 17, 1994, p. 26). The compound, also known as CL-20, was first synthesized in 1987. The method of synthesis and detailed performance data are still classified because of CL-20’s potential military application in rocket boosters and in warheads of “smart” weapons. The structure of CL-20 is
In such shorthand structures, each point where lines meet represents a carbon atom. In addition, the hydrogens attached to the carbon atoms are omitted; each of the six carbon atoms has one hydrogen atom attached. Finally, assume that the two O atoms in the NO2 groups are attached to N with one single bond and one double bond.
Three possible reactions for the explosive decomposition ofCL-20 are
i.
ii. C6H6N12O12(s) → 3CO(g) + 3CO2(g) + 6N2(g) + 3H2O(g)
iii. C6H6N12O12(s) → 6CO2(g) + 6N2(g) + 3H2 (g)
a. Use bond energies to estimate ∆E for these three reactions.
b. Which of the above reactions releases the largest amount of energy per kilogram of CL-20?
(a) (i)
Interpretation: The change in energy for the given chemical reactions has to be calculated.
Concept introduction: In a chemical reaction, energy is either gained, endothermic reactions, or released, exothermic reactions. The change in energy can be stated as the difference between the energy required to break the bonds in case of reactants and the energy released on the formation of the products.
To determine: The change in energy for the stated reactions.
Answer to Problem 155CP
The change in energy
Explanation of Solution
Given
The chemical reaction involved is,
Formula
Energy for reactants,
The total energy
For products,
The total energy
The change in energy
(ii)
Interpretation: The change in energy for the given chemical reactions has to be calculated.
Concept introduction: In a chemical reaction, energy is either gained, endothermic reactions, or released, exothermic reactions. The change in energy can be stated as the difference between the energy required to break the bonds in case of reactants and the energy released on the formation of the products.
To determine: The change in energy for the stated reactions.
Answer to Problem 155CP
The change in energy
Explanation of Solution
Given
The chemical reaction involved is,
Formula
Energy for reactants,
The total energy
For products,
The total energy
The change in energy
(iii)
Interpretation: The change in energy for the given chemical reactions has to be calculated.
Concept introduction: In a chemical reaction, energy is either gained, endothermic reactions, or released, exothermic reactions. The change in energy can be stated as the difference between the energy required to break the bonds in case of reactants and the energy released on the formation of the products.
To determine: The change in energy for the stated reactions.
Answer to Problem 155CP
The change in energy
Explanation of Solution
Given
The chemical reaction involved is,
Formula
Energy for reactants,
The total energy
For products,
The total energy
The change in energy
The change in energy can be stated as the difference between the energy required to break the bonds in case of reactants and the energy released on the formation of the products.
(b)
Interpretation: The change in energy for the given chemical reactions has to be calculated.
Concept introduction: In a chemical reaction, energy is either gained, endothermic reactions, or released, exothermic reactions. The change in energy can be stated as the difference between the energy required to break the bonds in case of reactants and the energy released on the formation of the products.
To determine: The reaction that releases the larger amount of energy per kilogram of
Answer to Problem 155CP
The reaction (iii) releases the largest amount of energy per kilogram of
Explanation of Solution
One mole of
In case of the (i) reaction,
Hence,
In case of the (ii) reaction,
Hence,
In case of the (iii) reaction,
Hence,
The reaction (iii) releases the largest amount of energy per kilogram of
The third stated reaction releases the largest amount of energy per kilogram of
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