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.
: Determine the molar enthalpy change for reaction 2
NH4Cl(aq) + NaOH(aq) ® NaCl(aq) + NH3(aq) + H2O(l) DH2 =
Using the solution procedure similar to that of the sample problem shown on page 2, calculate the molar heat of enthalpy, in kJ/mol NH4Cl, of reaction 2 given the following procedure and data information.
- Measure 50.0 mL of 2.00 M NaOH into the coffee cup calorimeter
- Measure 50.0 mL of 2.00 M NH4Cl into a glass beaker
- Collect the initial temperature of both solutions
- Add the 50.0 mL of 2.00 M NaOH into the coffee cup calorimeter all at once
- Use the thermometer to gently and continuously stir the mixture in order to disperse the heat evenly thorough the solution
- Continue to monitor the temperature until it maxes out. Record the highest temperature.
- Assume all solutions have a density = 1.03 g/mL and a heat capacity = 4.18 J/g×°C
Temperature data: Temperature of the solutions before mixing: 21.3 °C
Maximum temperature of the reaction mixture: 22.4 °C
|
In the space below, show all calculation set-ups to determine the molar heat of enthalpy, in kJ/mol HCl, of reaction 2 (DH2). |
Trending now
This is a popular solution!
Step by step
Solved in 4 steps with 3 images
