1. 2 nd Law of Thermodynamics, Entropy, heat calculations Thursday, January 15, 2014

2. Thursday, 1/15  Respond to the following on your warm-up sheet Describe the first law of thermodynamics and give a real world example of the law. Upcoming dates:  Thursday, 1/22 – Thermodynamics quiz  Monday, 1/26 – Thermodynamics test  Monday, 1/26 – Thermodynamics project due (15 minutes after the bell rings).  Thursday, 2/5 – Waves Quiz  Friday, 2/6 – 4SW extra credit due by 4:00 PM  Friday, 2/13 – Waves Quiz  Friday, 2/13 – End of 4SW  Wednesday, 2/18 – Waves Test (5SW)

3. Notes - Entropy  Review the following slides and add to your notes.

4. Processes in nature Types of processes  Reversible – is a process that after it’s finished can go backwards and end up where it started.  Irreversible – is a process that cannot go back and restore itself  All processes that occur in nature are irreversible (ex. a flower pot is dropped and shatters on the ground – the pot cannot be restored to it’s original state on its own).

6. Entropy  Is a measure of disorder of a system ‪ Diagram source cnx.orgcnx.org

9. Entropy  Relating entropy to different states of matter  When a substance is in a gas stage there’s more disorder than there is in a liquid stage because the molecules are held closer together in a liquid form.  When a substance is in a liquid stage there’s more disorder than there is in a solid stage because the molecules are held closer together in a solid stage. ‪ Diagram sources www2.ucdsb.on.ca ‪ Diagram sources www2.ucdsb.on.ca and ‪ cnx.org ‪ cnx.org

10. Restating the 2 nd Law of Thermodynamics  Natural processes tend to move toward a state of greater entropy.

11. Notes - specific heat, measuring heat energy  Review the following slides and add to your notes.

12. Let’s think… Do you think all substances/objects gain and lose heat at the same rate? Tell your elbow partner your thoughts and explain your position.

13. What is specific heat?  Every substance gains or loses heat based on its identity/physical property.  The physical property of a substance is its specific heat capacity.

14. Examples of specific heat

15. What is specific heat capacity?  Is the amount of heat (thermal energy) required to raise a unit of mass of the substance by one degree of temperature (liquids and solids).  Measure of how much thermal energy is required to change the temperature of a substance.

16. What is the equation for calculating heat change

17. How do you determine if heat is gained or lost  If heat energy is gained Q is positive.  If heat energy is lost Q is negative.

18. Example problem