1. Chemistry 202 Dr. Don DeCoste 367J Noyes Lab decoste@illinois.edu 11am-12pm Mondays and Wednesdays (after lecture) 10-11 am Tuesdays and 1-2 pm Thursdays By appointment; open door policy 1

2. Lon-Capa 1 st HW assignment due Friday, 9/4, 5 pm. It is open now. 1 st Quiz due Sunday, 9/6 by 10 pm. It will open Wednesday, 9/2 at 5 pm. 2

3. Chemistry Learning Center 230 Davenport Hall Chemistry TAs available from 9 am – 5pm Mondays – Fridays. Chemistry 202 TAs in the CLC: Mondays: 11am-1pm, 3pm-5pm Wednesdays: 3pm-5pm Thursdays: 3pm-5pm 3

4. For Monday Continue working on Lon-Capa. Finish reading Chapter 3 and doing the Chapter 3 homework (Challenge Problems!). Start reading Chapter 4 and doing the Chapter 4 homework. See me or email me if there are any questions or concerns. 4

5. Chemical Reaction 5

6. Clicker Question Balance the following equation and determine the sum of the coefficients: C 2 H 5 OH + O 2 → CO 2 + H 2 O A)4 B)5 C)8 D)9 E)10 6

7. Limiting Reactant Concept Hydrogen (H 2 ) and nitrogen (N 2 ) react to form ammonia (NH 3 ). 7

8. Make Sure You Can Do This… 500.0 g of hydrogen gas and 500.0 g of oxygen gas are reacted to form water. Determine the mass of water produced (563.0 g) and the mass of excess reactant left over (437.0g H 2 ). Prove mass has been conserved. (500.0 g + 500.0 g = 563.0 g + 437.0 g) 8

9. A Complex Problem Baking soda (sodium bicarbonate) decomposes upon heating to form sodium carbonate, water vapor, and carbon dioxide. Sodium carbonate does not decompose further at this temperature. You have a 10.00 g mixture of baking soda and sodium carbonate and heat it until completion. After heating you are left with 8.97 g of solid. Determine the mass percent of baking soda in the original mixture. 9

10. 10 Problem Solving: A Journey Where Are We Going?: What are we trying to solve? What does this mean? Where Have We Been?: What do we know? What is given in the problem, and what is our knowledge base? How Do We Get There?: How do we connect what we know to what we are trying to solve?

11. 11 Office Hours: My Contribution Yes you can. What are you looking for? OK, write that down … So what does this mean? OK, write that down. OK … Sure, no problem at all.