The compound heptane, C7H16, is a good fuel. It is a liquid at ordinary temperatures. When the liquid is burned, the reaction involved is C7H16() +11 O₂(g) 7 CO₂(g) + 8 H₂O(g) The standard enthalpy of formation of liquid heptane at 25 °C is -224.2 kJ mol-¹; other relevant enthalpy of formation values in kJ mol-¹ are: C7H16(9) -187.6; CO₂(g) = -393.5; H₂O(g) = -241.8 (a) Calculate the enthalpy change in the burning of 4.000 mol liquid heptane to form gaseous products at 25°C. State explicitly whether the reaction is endothermic or exothermic. ΔΗ° = (b) Would more or less heat be evolved if gaseous heptane were burned under the same conditions? v What is the standard enthalpy change for vaporizing 4.000 mol C7H16() at 25°C? ΔΗ° = kJ KJ Calculate the enthalpy change in the burning of 4.000 mol gaseous heptane to form gaseous products at 25°C. ΔΗ° = kJ
The compound heptane, C7H16, is a good fuel. It is a liquid at ordinary temperatures. When the liquid is burned, the reaction involved is C7H16() +11 O₂(g) 7 CO₂(g) + 8 H₂O(g) The standard enthalpy of formation of liquid heptane at 25 °C is -224.2 kJ mol-¹; other relevant enthalpy of formation values in kJ mol-¹ are: C7H16(9) -187.6; CO₂(g) = -393.5; H₂O(g) = -241.8 (a) Calculate the enthalpy change in the burning of 4.000 mol liquid heptane to form gaseous products at 25°C. State explicitly whether the reaction is endothermic or exothermic. ΔΗ° = (b) Would more or less heat be evolved if gaseous heptane were burned under the same conditions? v What is the standard enthalpy change for vaporizing 4.000 mol C7H16() at 25°C? ΔΗ° = kJ KJ Calculate the enthalpy change in the burning of 4.000 mol gaseous heptane to form gaseous products at 25°C. ΔΗ° = kJ
Chemistry
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Chapter1: Chemical Foundations
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Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...
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Thermochemistry
Thermochemistry can be considered as a branch of thermodynamics that deals with the connections between warmth, work, and various types of energy, formed because of different synthetic and actual cycles. Thermochemistry describes the energy changes that occur as a result of reactions or chemical changes in a substance.
Exergonic Reaction
The term exergonic is derived from the Greek word in which ‘ergon’ means work and exergonic means ‘work outside’. Exergonic reactions releases work energy. Exergonic reactions are different from exothermic reactions, the one that releases only heat energy during the course of the reaction. So, exothermic reaction is one type of exergonic reaction. Exergonic reaction releases work energy in different forms like heat, light or sound. For example, a glow stick releases light making that an exergonic reaction and not an exothermic reaction since no heat is released. Even endothermic reactions at very high temperature are exergonic.
Question
V20
Transcribed Image Text:The compound heptane, C7H16, is a good fuel. It is a liquid at ordinary temperatures. When the liquid is burned, the reaction involved is
C7H16() +11 O₂(g) 7 CO₂(g) + 8 H₂O(g)
The standard enthalpy of formation of liquid heptane at 25 °C is -224.2 kJ mol-¹; other relevant enthalpy of formation values in kJ mol-¹ are:
C7H16(9) = -187.6; CO₂(g) = -393.5; H₂O(g) = -241.8
(a) Calculate the enthalpy change in the burning of 4.000 mol liquid heptane to form gaseous products at 25°C. State explicitly whether the reaction is
endothermic or exothermic.
ΔΗ° =
(b) Would more or less heat be evolved if gaseous heptane were burned under the same conditions?
What is the standard enthalpy change for vaporizing 4.000 mol C7H16(₂) at 25°C?
ΔΗ° =
kJ
Calculate the enthalpy change in the burning of 4.000 mol gaseous heptane to form gaseous products at 25°C.
AH° =
KJ
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