Macmillan Learning Revell SECOND EDITION q= A chemist dissolved an 12.7-g sample of KOH in 100.0 grams of water in a coffee cup calorimeter. When she did so, the water temperature increased by 27.6 °C. Based on this, how much heat energy was required to dissolve the sample of KOH? Assume the specific heat of the solution is 4.184 J/g °C. Calculate the heat of solution for KOH in kJ/mol. Macmillan Learning heat of solution = kJ kJ/mol
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.
![**Chemistry Experiment: Coffee Cup Calorimetry**
When a chemist dissolved a 12.7 g sample of potassium hydroxide (KOH) in 100.0 grams of water in a coffee cup calorimeter, the temperature of the water increased by 27.6°C. To calculate the heat energy required to dissolve the KOH sample, assume the specific heat capacity of the solution is 4.184 J/g°C.
Firstly, calculate the heat absorbed (q) by the water using the formula:
\[ q = m \cdot c \cdot \Delta T \]
Where:
- \( m \) is the mass of the water (100.0 g)
- \( c \) is the specific heat capacity (4.184 J/g°C)
- \( \Delta T \) is the change in temperature (27.6°C)
Complete the calculation to find the value of \( q \) in kJ.
Next, calculate the heat of solution for KOH in kJ/mol. For this calculation, consider the moles of KOH dissolved in the solution. Use the molar mass of KOH to convert grams to moles and complete the following calculation:
\[ \text{Heat of solution (kJ/mol)} = \frac{q \text{ (kJ)}}{\text{moles of KOH}} \]
**Graph/Diagram Explanation:**
There are no graphs or diagrams in this document. Instead, there are two calculations to be completed to find the values of heat absorbed and the heat of solution. Rectangular boxes are provided for entering the calculated values for \( q \) in kJ, and for the heat of solution in kJ/mol.](/v2/_next/image?url=https%3A%2F%2Fcontent.bartleby.com%2Fqna-images%2Fquestion%2F6a54ba52-8823-45a4-bdfc-14d625ac2519%2F0f417b40-ec06-4f86-b765-99b6d771ab7f%2Fycbhpv_processed.jpeg&w=3840&q=75)
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