1. A C RASH C OURSE IN T HERMODYNAMICS Darynn Magee

2. W HAT IS T HERMODYNAMICS ? The science of heat or energy flow in chemical reactions. The study of the transformation of energy into different forms

3. A B RIEF H ISTORY : Otto Von Guericke (1650): Designed the world’s first vacuum pump. Known as the Magdeburg Hemispheres, the hemispheres were held together with a force of over 20,000N or 4,500.lbs

4. A B RIEF H ISTORY : Robert Boyle and Robert Hooke (1656): Built the first air pump. During their studies, Boyle and hook noticed a correlation between temperature, pressure and volume. Developed Boyle’s Law

5. A B RIEF H ISTORY Sadi Carnot (1824): Known as “the father of thermodynamics” Published Reflections on the Motive Power of Fire.

6. A B RIEF H ISTORY : James Joule (1849): coined the term “thermodynamics” as the science of the relation between heat and power

7. T HE T HERMODYNAMICIST ’ S V IEW OF THE U NIVERSE : The universe is defined as: Universe = System + Surroundings

8. T YPES OF SYSTEMS : Open: Both mass and energy is exchanged between the system and its surroundings Closed: Energy is exchanged between the system and its surroundings but mass is conserved Isolated: No exchange of mass or energy between the system and its surroundings.

9. OPEN S YSTEMS

10. C LOSED S YSTEMS

11. I SOLATED SYSTEMS

12. E NERGY F LOW W ITHIN A S YSTEM Exothermic ReactionsExothermic Reactions: Energy flows from the system into its surroundings. The internal energy of the system goes down.

13. E NERGY F LOW W ITHIN A S YSTEM Endothermic reactionsEndothermic reactions: Energy flows from the surroundings to the system. Internal energy of the system goes up.

14. L AWS OF T HERMODYNAMICS 1 st law: The Law of Conservation of energy Energy cannot be created or destroyed. It can only change forms. The increase in the internal energy of a system is equal to the amount of energy added by heating the system, minus the amount lost as a result of the work done by the system on its surroundings. U=q-pΔV

15. L AWS OF T HERMODYNAMICS 1 st Law (continued): U=q-pΔV U= internal energy in joules (J) q= heat flow in joules (J) P= pressure in atmospheres (atm) ΔV= Change in volume (V 2 -V 1 ) in liters (L)

16. L AWS OF T HERMODYNAMICS 1 st law sample problem: A balloon with a volume of 1L and a pressure of 1 atm sits in the Sun for one hour. The Sun applies 100J of heat to the balloon and its volume increases to 1.25L. What is the internal energy of the balloon?

17. L AWS OF T HERMODYNAMICS Answer: 99.75J U=q-pΔV U=100-1(1.25-1) U=99.75J

18. L AWS OF T HERMODYNAMICS 2 nd Law: The entropy (disorder) of the universe is always increasing, for spontaneous reactions. Entropy is used to quantify the extent of disorder resulting from the dispersal of energy and matter Units of J/mol×K

19. L AWS OF T HERMODYNAMICS 2 nd law (continued): Disorder is more probable than order, so it stands that an ordered system will become disordered over time.

20. L AWS OF T HERMODYNAMICS 2 nd law (continued): The entropy of the universe increases naturally. Reducing the entropy of a system takes work. The entropy of the universe never goes down regardless of how much work we put into it. ↔

21. L AWS OF T HERMODYNAMICS 2 nd law (continued): The 2 nd law allows us to predict the equilibrium conditions of a given chemical process as well as the direction of spontaneous change towards equilibrium. If we took given amounts of reactants and products of a chemical reaction and mix them together, the 2 nd law would help us figure out how much of the reactants and products will be left over after the they are mixed.

22. L AWS OF T HERMODYNAMICS 3 rd law: As a system approaches absolute zero (0K), all processes cease and the entropy of the system approaches a minimum value. The most ordered state is a crystalline structure at 0K. There is no entropy (disorder) in a crystalline structure at 0K. Entropy = 0. Other physical states at 0K can have residual entropy.

23. L AWS OF T HERMODYNAMICS 3 rd law (continued): The entropy of a substance is the amount of entropy gained in order to convert it from a crystalline structure at 0K to its current form. In general, in terms of entropy: Solid < liquid < gas

24. W RAP U P What are the characteristics of open, closed, and isolated systems? Give some examples of each What are endothermic and exothermic reactions? How does the system do work on its surroundings when the heat is applied? (1 st law) What is entropy? (2 nd law) What would the world be like if there was no entropy? (3 rd law)