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

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Lon-Capa

1st HW assignment due Friday, 9/4, 5 pm. It is open now.

1st Quiz due Sunday, 9/6 by 10 pm. It will open Wednesday, 9/2 at 5 pm.

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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

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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.

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Chemical Reaction

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Clicker Question

Balance the following equation and determine the sum of the coefficients:

C2H5OH + O2 → CO2 + H2O

A) 4B) 5C) 8D) 9E) 10 6

Limiting Reactant Concept

Hydrogen (H2) and nitrogen (N2) react to form ammonia (NH3).

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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 H2).

Prove mass has been conserved.(500.0 g + 500.0 g = 563.0 g + 437.0 g)

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A Complex ProblemBaking 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.

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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?

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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, write that down. OK … Sure, no problem at all.