1. Unit 10:
Thermodynamics

2. Review:
A piece of metal at 500oC is added to a beaker containing 150 grams of water. The temperature of the water is monitored with a thermometer and it increases from 25oC to 32oC. What quantity of heat was transferred to the water? Water has a c = 𝐽 𝑔 𝑜 𝐶
500oC

3. 1. Bond dissociation energies 3. Enthalpies of formation
2. Hess’ Law
Enthalpy: Methods of Calculation
4. Calorimetry

4. 1. Bond dissociation energies 3. Enthalpies of formation
2. Hess’ Law
Enthalpy: Methods of Calculation
4. Calorimetry
4. Lab Method - Calorimetry
In the review, q=mC∆T told us how much heat the metal transferred to the water
500oC
Calorimetry uses the same concept, except instead of a solid object that releases or absorbs heat, a reaction is performed in the water!
Reaction!

5. 1. Bond dissociation energies 3. Enthalpies of formation
2. Hess’ Law
Enthalpy: Methods of Calculation
4. Calorimetry
4. Lab Method - Calorimetry
By measuring the ∆T of the water, you can calculate the heat released or absorbed by the reaction.
THIS IS THE ENTHALPY!!!
Reaction!

6. Similarities and Differences:
Here there are clearly defined masses, one that increases temp. and another that decreases.
Here, the water will change temp., but there is no other mass to change temperature.

7. What is the enthalpy of solution of HCl?
Temperature of the sol’n increased from 25oC to 30oC
What is the enthalpy of solution of HCl?
Water, 100 g
HCl
0.5 moles
(increases sol’n mass to 118 g)

8. A chemistry student dissolves 4. 51 grams of sodium hydroxide in 100
A chemistry student dissolves 4.51 grams of sodium hydroxide in mL of water at 19.5°C (in a calorimeter). As the sodium hydroxide dissolves, the temperature of the solution increases to 31.7°C. Determine the heat of solution of the sodium hydroxide in J/g.

10. Work on Specific Heat Experiment WOrksheet

11. Calorimetry Lab: Compound X: NaOH Compound Y: NH4NO3
Actual enthalpies of solution for NaOH and NH4NO kJ/mol and kJ/mol