The heat of combustion (AH) for propane (molar mass 44.11 g/mol) is -2222 kJ/mol. The heat generated from burning 2.195 g of propane is used to heat 575.0 g of water in a calorimeter. What is the change in temperature (°C) of the water? (The molar heat capacity of water is 75.38 J/mol °C).
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 2 of 10**
The heat of combustion (ΔH) for propane (molar mass 44.11 g/mol) is -2222 kJ/mol. The heat generated from burning 2.195 g of propane is used to heat 575.0 g of water in a calorimeter. What is the change in temperature (°C) of the water? (The molar heat capacity of water is 75.38 J/mol·°C).
**Details for solution:**
1. **Determine moles of propane burned:**
\[
\text{moles of propane} = \frac{2.195 \text{ g}}{44.11 \text{ g/mol}}
\]
2. **Calculate the heat released:**
\[
\text{Heat released} (q) = \text{moles of propane} \times (-2222 \text{ kJ/mol})
\]
3. **Convert kJ to J (1 kJ = 1000 J):**
4. **Calculate the change in temperature using the formula:**
\[
q = m \cdot c \cdot \Delta T
\]
where \( m \) is the mass of water, \( c \) is the molar heat capacity of water, and \( \Delta T \) is the change in temperature.
5. **Rearrange for \( \Delta T \):**
\[
\Delta T = \frac{q}{m \cdot c}
\]
Solve for \( \Delta T \) to find the change in temperature of the water.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F38543b38-0ca2-4898-a226-639f5edfcbc9%2F45ac2145-d447-4d5b-b615-e2e2410d6818%2Feqopokm_processed.jpeg&w=3840&q=75)
Given data
The heat of combustion for propane is -2222 kJ/mol.
Mass 2.195 g of
575.0 g of water
The molar heat capacity of water is 75.38 J/mol. C).
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