1. Unit 4 - 1
Entropy and Enthalpy

2. January 6, 2015 – 96 minutes

3. Do Now January 6, 2015
In your own words or pictures, describe the difference between endothermic and exothermic reactions.

4. Do Now January 6, 2015
Endothermic reactions absorb energy to move forward
Exothermic reactions release energy to move forward

5. Objective
I can construct particle diagrams to demonstrate my understanding of the vocabulary term entropy.

6. Agenda Do Now, Objective (8 min) 2nd Semester Housekeeping
Vocabulary (6 min)
Guided Reading (15 – 25 min)
Chemistry Review Questions ( min)
Exit Ticket (5 min)
Semester 1 Exam Review (10 – 20 min)

7. Grading Policy – 2nd Semester
Tests – 25%
Quizzes – 20%
Semester Exam – 20%
Classwork – 15%
Labwork – 10%
Homework – 10% (must be turned in ON TIME. Late work will receive ½ credit)

8. Tutoring Hours - 2nd Semester
Tuesday 3:30 – 4:30 PM
Thursday 3:30 – 4:30 PM
Friday Lunch
All other tutoring is by appointment only

9. Test Retakes
Unit tests may be retaken one time. Students who are absent on the day of the test must take it on a retake day.
Students must attend scheduled retake tutoring in order to retake the test
All retakes must be taken within 1 week of the original test.

10. Homework – HW #1
Make a picture that shows entropy increasing in a situation. Write an explanation of your picture including how it shows entropy increasing. You may draw this and hand it in, or take a picture and send it to with the subject line Homework #1
Due Next Class!

11. Entropy (S)
The disorder of particles in a substance. Entropy always tends to increase, that is order goes to disorder.
Change in Entropy is ΔS

12. Guided Reading Graded Assignment
Complete your guided reading silently at your table.
Answer all questions on a separate sheet of paper

13. Energy and Entropy Changes in Chemical Reactions
Law of Conservation of Energy: energy can’t be created or destroyed, it can only change form
Chemical bonds hold the atoms in a molecule together (strong)
Attractive forces hold the molecules in solids and liquids together (weak)
Breaking chemical bonds takes energy = endothermic
Forming chemical bonds releases energy = exothermic

14. Bonds vs. Attractive Forces

15. Particle Diagrams & Entropy (S)

16. Chem Review Questions
Use your whiteboard to answer the following questions.

17. Chem Review Questions
Identify each of the following changes as endothermic, exothermic, or not possible to tell. Explain your decision in each case.
When effervescent antacid tablets are dropped into water, the tablets slowly disappear and the water becomes fizzy
It is impossible to tell because no heat energy information is provided

18. Chem Review Questions
Identify each of the following changes as endothermic, exothermic, or not possible to tell. Explain your decision in each case.
On a hat day, water vapor condenses out of the air and turns into liquid droplets on the outside of a cold glass of lemonade
The change is exothermic because water molecules have less energy as a liquid than as a vapor because they experience less movement in the liquid state. Condensation is an exothermic process.

19. Chem Review Questions
Identify each of the changes listed in Question 1 as disorder (spreadedness) increases, disorder (spreadedness) decreases, or not possible to tell. Explain your decision in each case.
When effervescent antacid tablets are dropped into water, the tablets slowly disappear and the water becomes fizzy
Disorder increases because a solid dissolves in water and a gas is produced.

20. Chem Review Questions
Identify each of the changes listed in Question 1 as disorder (spreadedness) increases, disorder (spreadedness) decreases, or not possible to tell. Explain your decision in each case.
On a hat day, water vapor condenses out of the air and turns into liquid droplets on the outside of a cold glass of lemonade
Disorder decreases because liquid molecules are more attracted to each other and are less free to move than gas molecules.

21. 4Fe(s) + 3O2(g)  2Fe2O3(s) and 2KClO3(s)  2KCl(s) + 3O2(g)
Chem Review Questions
Use the following chemical equations to answer parts (a) and (b)
4Fe(s) + 3O2(g)  2Fe2O3(s) and 2KClO3(s)  2KCl(s) + 3O2(g)
Identify the reactants and the products in each chemical equation
Decide if each change represents an increase in disorder or decrease in disorder. Explain your choice in each case.

22. 4Fe(s) + 3O2(g)  2Fe2O3(s) and 2KClO3(s)  2KCl(s) + 3O2(g)
Chem Review Questions
Use the following chemical equations to answer parts (a) and (b)
4Fe(s) + 3O2(g)  2Fe2O3(s) and 2KClO3(s)  2KCl(s) + 3O2(g)
Identify the reactants and the products in each chemical equation
Reactants: Fe and O2; Products: Fe2O3
Reactants: KClO3; Products: KCl and O2
Decide if each change represents an increase in disorder or decrease in disorder. Explain your choice in each case.
Disorder decreases because a gas is consumed and a solid is produced.
Disorder increases because a gas is produced while no gases are consumed.

23. Exit Ticket
Silently complete your exit ticket and turn it in to Ms. B when you are finished.

24. Fun Entropy Videos
Neil deGrasse Tyson and Entropy
cox/videos/wonders-of-the-universe-entropy.htm Entropy and Sand
Bozeman Science

25. Semester 1 Final Exam
Look over your final exam, and when you have recorded your grade, return it to Ms. Bergman
STRENGTHS
AREAS FOR GROWTH
Forms of Energy
Atomic Structure
Chemical Reactions
Bonding
Law of Conservation of Energy