1. CHEMISTRY Please take out:  Intro to Keq worksheet (gray)  Intro K eq vs. Q #2 worksheet (yellow)  Your notebook ready for the warm-up Ask your partner, “How did the homework go for you? Did you hear that we didn’t have to do #9 on the gray worksheet?

2. Warm-up Carbon monoxide gas is added to oxygen gas to form carbon dioxide gas. 1. Write a balanced chemical equation for this reaction. 2. Write the equilibrium expression for this reaction 3. Calculate K eq if [CO]= 2.5 x 10 -3 [O 2 ]=1.6 x 10 -3 [CO 2 ]= 3.2 x 10 -2 4. What does the value of K tell you about the equilibrium mixture? 5. Would this reaction be endo- or exothermic? 6. Draw a sketch of an energy diagram that would make sense for this reaction

3. Warm-up Energy Reaction R P Higher Energy Lower Energy 100000

4. Learning Targets I can connect K eq with endo/exothermic reactions and energy diagrams I can calculate Q for an equilibrium reaction and predict which way a reaction will go by comparing Q to K eq I can calculate the concentration of reactants and products at equilibrium when given their initial concentration using ICE boxes.

5. Homework Review Compare your answers to the gray worksheet (except #9) and 1-18 of the Intro to Keq worksheet with your lab group Be prepared to ask questions in 5 minutes.

6. Quick Whiteboard PhET Check-in Grab one whiteboard and pen per person Share a tissue please If you’d like to grab your PhET homework from last class, you may!

7. Which reaction would probably appear to be quickest? A B C D

8. What would best describe what is in the container after several minutes have passed ?

9. Answer choices A.Container will have only & B.Container will have only & C.Container will have a mixture of all four with more & D.Container will have a mixture of all four with more &

10. A.Increase the number of & B.Increase the number of & C.Have no effect Using the heater would

11. What would best describe what is in the container after several minutes have passed ?

12. A.Container will have only & B.Container will have only & C.Container will have a mixture of all four with more & D.Container will have a mixture of all four with more & Answer choices

13. What would best describe what is in the container after several minutes have passed ?

14. Answer choices A.Container will have mostly & B.Container will have mostly & C.Container will have a mixture of all four with nearly equal amounts D.No reaction will occur since the products and reactants have the same energy

15. At equilibrium, what would you predict is in the container?

16. data

17. Answer choices A.Container will have mostly & B.Container will have mostly & C.Container will have a mixture of all four with nearly equal amounts D.No reaction will occur since the products and reactants have the same energy

18. Which best shows that equilibrium has been reached? A.The number of reactants is greater than the products B.The number of products is greater than the reactants C.The number of products is equal to the reactants D.The number of products and reactants remains constant

19. At equilibrium, what would you predict is in the container?

20. Answer choices A.Container will have only & B.Container will have only & C.Container will have a mixture of all four with more & D.Container will have a mixture of all four with more &

21. NOTES: KEQ VS. Q

22. Why is “K” called a constant? K is a ratio of [products] to [reactants] Its value does not change when the concentration of the reactants or products are changed. The concentrations will find “their” balance no matter the concentrations you start with Values for K are determined experimentally

23. Reaction Quotient (Q) Snapshot at a specific time in the reaction Tells us if a reaction is at equilibrium yet Used to Predict if more P or R will be made to reach equilibrium (K eq ) Calculate Q the same way as a K eq, but compare Q vs. a given K eq K eq = Q, reaction already at equilibrium K eq >Q, rxn will go  Right (will make more P) K eq <Q, rxn will go  Left (will make more R) If you write K and Q in alphabetical order, the greater than/less than sign points in the direction!

25. Q vs. Keq Problem: Try this one! If the K eq = 0.25 at 340°C for Fe 2 O 3(s) + 3H 2(g) ⇆ 2Fe (s) + 3H 2 O (g) Given that [H 2 ] = 0.46 M and [H 2 O] = 0.060 M, find Q and determine the direction the reaction will proceed

26. Discuss with your partner and be prepared to share Why do these statements make sense? – If K eq is a large number: more products – If K eq is a small number: more reactants What is the difference between K and Q? Why do these statements make sense? – Q = K eq, reaction already at equilibrium – Q < K eq, reaction proceeds from left to right (makes products) – Q > K eq, reaction proceeds from right to left (make reactants)

27. Keq vs. Q Practice Complete problems 19-26 on your Intro to K eq worksheet and be prepared to check answers in 10-15 minutes.

28. New Skill! How do we calculate the new concentrations of our reactants after they’ve formed products and reached equilibrium? Aka, just like #9 asked you on the gray worksheet!

29. In your notes If A + B ⇆ C This reaction starts with 0.5M of A and 0.3M of B. At equilibrium, there is 0.2 M of C. What is the concentration of A and B at equilibrium? Skill: Set up an ICE box A + B ⇆ C Initial [ ] Change Eq. value

30. Answer A + B  C This reaction starts with 0.5M of A and 0.3M of B. At equilibrium, there is 0.2 M of C. What is the concentration of A and B at equilibrium? A + B ⇆ C Initial 0.5 M 0.3M 0M Change - 0.2 M -0.2 M +0.2M Eq. value 0.3 M 0.1 M 0.2 M

31. Now try this one … D + 2 E ⇆ F The reaction takes place in a 2 L container and starts with 0.8 moles of D and 1.6 moles of E. At equilibrium, 0.6 moles of F are formed. What are the concentrations of D and E at equilibrium? Hint: You have to take into account the mole ratio.

32. Now try this one… D + 2 E ⇆ F The reaction takes place in a 2 L container and starts with 0.8 moles of D and 1.6 moles of E. At equilibrium, 0.6 moles of F are formed. What are the concentrations of D and E at equilibrium? **Hint: Use molar ratios! D + 2E ⇆ F Initial 0.4M 0.8M 0M Change - 0.3M -0.6M +0.3M Eq. value 0.1M 0.2M 0.3M Key points: Change moles to M before using the ICE box (divide moles by 2L) Subtract (0.3 x 2) from E because the ratio of F:E is a 1:2 ratio!

33. Homework due Thursday/Friday Complete Pre-Lab Finish ICE Box worksheet We will go over specifics of procedure on Thursday and do the lab! Yay!!!!!!