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.
Definition Definition Transformation of a chemical species into another chemical species. A chemical reaction consists of breaking existing bonds and forming new ones by changing the position of electrons. These reactions are best explained using a chemical equation.
Chapter 3, Problem 153CP
(a) (i)
Interpretation Introduction
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.
(a) (i)
Expert Solution
Answer to Problem 153CP
The change in energy
=-2635.5kJ_
Explanation of Solution
Given
The chemical reaction involved is,
C6H6N12O12(s)→6CO(g)+6N2(g)+3H2O(g)+32O2(g)
Formula
The change in energy =(Energy required to breakthe bonds in reactants)–(Energy released whenproductsareformed)
Energy for reactants,
6C−H=413kJ1mol×6mol=2478kJ
6N=O=607kJ1mol×6mol=3642kJ
3C−C=347kJ1mol×3mol=1041kJ
12C−N=305kJ1mol×12mol=3660kJ
6N−N=160kJ1mol×6mol=960kJ
The total energy
=(3660+1041+960+3642+2478)kJ=12987kJ (1)
For products,
6C≡O=1072kJ1mol×6mol=6432kJ
6N≡N=941kJ1mol×6mol=5646kJ
6O−H=467kJ1mol×6mol=2802kJ
32O=O=495kJ1mol×32mol=742.5kJ
The total energy
=(6432+5646+2802+742.5)kJ=15622.5kJ (2)
The change in energy
=(12987-15622.5)kJ=-2635.5kJ_ (from equation (1) and (2))
(ii)
Interpretation Introduction
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.
(ii)
Expert Solution
Answer to Problem 153CP
The change in energy
=-3147kJ_
Explanation of Solution
Given
The chemical reaction involved is,
C6H6N12O12(s)→3CO(g)+3CO2(g)+6N2(g)+3H2O(g)
Formula
The change in energy =(Energy required to breakthe bonds in reactants)–(Energy released whenproductsareformed)
Energy for reactants,
6C−H=413kJ1mol×6mol=2478kJ
6N=O=607kJ1mol×6mol=3642kJ
3C−C=347kJ1mol×3mol=1041kJ
12C−N=305kJ1mol×12mol=3660kJ
6N−N=160kJ1mol×6mol=960kJ
The total energy
=(3660+1041+960+3642+2478)kJ=12987kJ (1)
For products,
3C≡O=1072kJ1mol×3mol=3216kJ
6C=O=745kJ1mol×6mol=4470kJ
6N−N=941kJ1mol×6mol=5646kJ
6O−H=467kJ1mol×6mol=2802kJ
The total energy
=(3216+4470+5646+2802)kJ=16134kJ (2)
The change in energy
=(12987-16134)kJ=-3147kJ_ (from equation (1) and (2))
(iii)
Interpretation Introduction
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.
(iii)
Expert Solution
Answer to Problem 153CP
The change in energy
=-4191kJ_
Explanation of Solution
Given
The chemical reaction involved is,
C6H6N12O12(s)→6CO2(g)+6N2(g)+6H2(g)
Formula
The change in energy =(Energy required to breakthe bonds in reactants)–(Energy released whenproductsareformed)
Energy for reactants,
6C−H=413kJ1mol×6mol=2478kJ
6N=O=607kJ1mol×6mol=3642kJ
3C−C=347kJ1mol×3mol=1041kJ
12C−N=305kJ1mol×12mol=3660kJ
6N−N=160kJ1mol×6mol=960kJ
The total energy
=(3660+1041+960+3642+2478)kJ=12987kJ (1)
For products,
12C=O=745kJ1mol×12mol=8940kJ
6N−N=941kJ1mol×6mol=5646kJ
6H−H=432kJ1mol×6mol=2592kJ
The total energy
=(8940+5646+2592)kJ=17178kJ (2)
The change in energy
=(12987-17178)kJ=-4191kJ_ (from equation (1) and (2))
Conclusion
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 Introduction
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
CL−20.
(b)
Expert Solution
Answer to Problem 153CP
The reaction (iii) releases the largest amount of energy per kilogram of
CL−20.
Explanation of Solution
One mole of
C6H6N12O12 gives
438g.
In case of the (i) reaction,
438g of the reactant gives energy
=−2635.5kJ
Hence,
1kg of the reactant gives energy
=−2635.5438×1000kJ=-6017.12kJ
In case of the (ii) reaction,
438g of the reactant gives energy
=−3147kJ
Hence,
1kg of the reactant gives energy
=−3147438×1000kJ=-7184.9kJ
In case of the (iii) reaction,
438g of the reactant gives energy
=−4191kJ
Hence,
1kg of the reactant gives energy
=−4191438×1000kJ=-9568.49kJ_
The reaction (iii) releases the largest amount of energy per kilogram of
CL−20.
Conclusion
The third stated reaction releases the largest amount of energy per kilogram of
CL−20.
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