Part A Click the AH is an Extensive Property button within the activity, and analyze the relationship between the two reactions that are displayed. The reaction that was on the screen when you started and its derivative demonstrate that the change in enthalpy for a reaction, AH, is an extensive property. Using this property, calculate the change in enthalpy for Reaction 2. Reaction 1: C3HS(g) + 502(g)→3CO2(g) +4H20(g), AĦ1 = -2043 kJ Reaction 2: 5C, Hs(g) +2502(g)→15CO2(g) + 20H2O(g), AH2 =? Express your answer to four significant figures and include the appropriate units. • View Available Hint(s) HA ? AH = Value kJ
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.
![Open the activity depicting Hess's Law.
**Part A**
Click the "ΔH is an Extensive Property" button within the activity, and analyze the relationship between the two reactions that are displayed. The reaction that was on the screen when you started and its derivative demonstrate that the change in enthalpy for a reaction, ΔH, is an extensive property. Using this property, calculate the change in enthalpy for Reaction 2.
- **Reaction 1:** \( \text{C}_8\text{H}_{18}(g) + 5\text{O}_2(g) \rightarrow 3\text{CO}_2(g) + 4\text{H}_2\text{O}(g), \, \Delta H_1 = -2043 \, \text{kJ} \)
- **Reaction 2:** \( c \times 5\text{C}_8\text{H}_{18}(g) + 25\text{O}_2(g) \rightarrow 15\text{CO}_2(g) + 20\text{H}_2\text{O}(g), \, \Delta H_2 = ? \)
**Express your answer to four significant figures and include the appropriate units.**
- **Hint:** View Available Hint(s)
**ΔH₂ =** [Value] kJ
### Explanation of Diagram in Activity
The diagram on the left includes three key points:
1. **ΔH is an Extensive Property:**
- This section demonstrates that the enthalpy change depends on the quantity of material present in the reaction.
2. **ΔH Changes Sign When a Process is Reversed:**
- This highlights that reversing a chemical equation will invert the sign of ΔH.
3. **Hess's Law of Constant Heat Summation:**
- The diagram visually represents how individual reactions can be algebraically summed to find the total enthalpy change. It shows that by adding or subtracting enthalpies of smaller steps, you can calculate the enthalpy change for the overall reaction. Reactions that get canceled out are marked appropriately to visualize the net equation.
This exercise illustrates the fundamental concepts of Hess's Law in thermochemistry, emphasizing the calculation of enthalpy changes for chemical reactions.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F4a2bd348-d826-4056-b9ee-5fd404bc60f1%2Ff2f36f42-9ae5-4ec8-aa4b-5bd7ce786886%2F14c83lm_processed.png&w=3840&q=75)

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