CHM 2046C Module 13 Chapter 16 Sample Exam Answers

Part K: Chapter 16 Key Terms 10 points

1. _entropy (S)_ – the amount of molecular randomness in a system

2. _first law of thermodyanics – The total internal energy of an isolated system is constant.

3. _Gibbs free energy (G) –. A thermodynamic state function relating enthalpy, temperature, and entropy

4. _second law of thermodyanmics_ - In any spontaneous process, the total entropy of a system and its surroundings always increases..

5. _spontaneous process_ – a process that proceeds on its own without any continuous external influence

6. _standard entropy of reaction (∆S^o )_ – entropy change under standard state conditions

7. _standard free-energy of formation (∆G^o_f )_-:The free-energy

change for formation of 1 mol of a substance in the standard state from the most stable form of the constituent elements in their standard states. :

8. _standard molar entropy (S^o)_ – the entropy of one mole of a pure substance at 1 atm pressure and a specific temperature, usually 25^oC for a gas, 1 M concentration for a solution

9. _standard-state _ The most stable form of an element or compound in the physical state in which it exists at 1 bar and the specific temperature. `.

10. thermodyamics – the study of the interconversion of heat and other forms of energy

11. _third law of thermodyanmics_ The entropy of a perfectly ordered crystalline substance at Zero Kelvin (0 K) is Zero

Review Terms:

12. _enthalpy change (∆H) – the heat change in a reaction or process at constant pressure ∆H = ∆E + P∆V

13. _thermodyanmic system – The substance being evaluated for energy content in a thermodynamic process.

14. _surroundings – everything outside the system in a thermodynamic process

15. _exothermic - a reaction in which heat is evolved and the temperature of the surroundings rises

16. _endothermic - a reaction in which heat is absorbed and the temperature of the surroundings falls

17. _State function – a quantity whose value is determined only by the state of the system

18. _standard heat (enthalpy) of formation (∆H^o_f) – the enthalpy change for the hypotheorical formation of 1 mol of a substance in the stanbdard state from the most stable forms of it constituent elements in their standard states.

19. __Isothermal Process__Heat flows into or out of a thermodynamic system so that there is no temperature chane in the system.

20. __adiabatic process__No heat may flow into or out of a thermodynamic system. The system is perfectly insulated from its surroundings