AP WORKSHEET 05c: Thermochemistry Summary
1. Sketch fully labeled, enthalpy level diagrams (reaction profiles) for;
(a) A single step reaction that is exothermic. (2)
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(b) A two step reaction in which an intermediate is formed in an exothermic reaction but
o
the overall reaction is endothermic. (4)
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1
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https://www.coursehero.com/file/77587781/05C-Thermochemistry-Summarypdf/
, -1
2. Butane, C4H10 has a standard enthalpy of combustion = -2881 kJ mol
(a) What is the significance of the negative sign associated with the enthalpy change? (1)
(b) Calculate the enthalpy change when 4.000 g of butane is completely burned. (2)
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er as
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eH w
o.
rs e
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-1 -1
(c) Assuming the specific heat capacity of water to be 4.200 J g K , and that in such a
aC s
reaction only 63.15 % of the energy generated is actually transferred to the water,
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calculate the change in temperature of 2.000 kg of water that is heated by burning the
butane in part (b) above. (4)
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ar stu
is
Th
sh
2
This study source was downloaded by 100000822948982 from CourseHero.com on 04-07-2021 17:44:47 GMT -05:00
https://www.coursehero.com/file/77587781/05C-Thermochemistry-Summarypdf/
1. Sketch fully labeled, enthalpy level diagrams (reaction profiles) for;
(a) A single step reaction that is exothermic. (2)
m
er as
co
eH w
o.
rs e
ou urc
(b) A two step reaction in which an intermediate is formed in an exothermic reaction but
o
the overall reaction is endothermic. (4)
aC s
vi y re
ed d
ar stu
is
Th
sh
1
This study source was downloaded by 100000822948982 from CourseHero.com on 04-07-2021 17:44:47 GMT -05:00
https://www.coursehero.com/file/77587781/05C-Thermochemistry-Summarypdf/
, -1
2. Butane, C4H10 has a standard enthalpy of combustion = -2881 kJ mol
(a) What is the significance of the negative sign associated with the enthalpy change? (1)
(b) Calculate the enthalpy change when 4.000 g of butane is completely burned. (2)
m
er as
co
eH w
o.
rs e
ou urc
o
-1 -1
(c) Assuming the specific heat capacity of water to be 4.200 J g K , and that in such a
aC s
reaction only 63.15 % of the energy generated is actually transferred to the water,
vi y re
calculate the change in temperature of 2.000 kg of water that is heated by burning the
butane in part (b) above. (4)
ed d
ar stu
is
Th
sh
2
This study source was downloaded by 100000822948982 from CourseHero.com on 04-07-2021 17:44:47 GMT -05:00
https://www.coursehero.com/file/77587781/05C-Thermochemistry-Summarypdf/
