Chemistry 202 Dr. Don DeCoste 3014 Chemistry Annex decoste@illinois.edu 11am-12pm Mondays and Wednesdays (after lecture) 10-11 am Tuesdays and 1-2 pm Thursdays By appointment; open door policy

Chemistry Learning Center 2021 Chemistry Annex Chemistry TAs available from 9 am – 5pm Mondays – Fridays. Link to the schedule is on the website (Contact Information) Chemistry 202 TAs in the CLC: Mondays: 11am – 1 pm Wednesdays: 3 – 5 pm Thursdays: 1 – 3 pm

Lon-Capa 1st HW assignment due Friday, 9/8, 10 pm. It is open now. 1st “Quiz” (2nd HW) due Sunday, 9/10 by 10 pm. It will open Friday, 9/8 at 5 pm.

For Today Textbook Homework Videos Chapter 3: Stoichiometry Challenge Problem: Chapter 3 #128 Chapter 4: Solution Stoichiometry Concentration and Dilution Precipitation Reactions and Solubility Rules

For Friday Textbook Homework Videos Chapter 4: Solution Stoichiometry Precipitation Stoichiometry I: Net Ionic Equations Precipitation Stoichiometry II: Complete Equations Challenge Problem: Chapter 4 #121

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.

Challenge Problem: Ch. 3

Clicker Question Consider the balanced chemical equation: 4A + 3B → 2C + D When equal masses of A and B are reacted, which is limiting? a) If the MMA > MMB, then A must be limiting. b) If the MMA < MMB, then A must be limiting. c) If the MMA > MMB, then B must be limiting. d) If the MMA < MMB, then B must be limiting e) None of the above must be true.

Clicker Question You dissolve equal mass samples of different ionic compounds in separate beakers to make five solutions with equal volumes. Which of the following has the highest concentration in terms of molarity?   a) lithium chloride b) potassium sulfate c) sodium carbonate d) magnesium nitrate e) I am not sure how to do this.

Formulas for Ionic Compounds are Empirical Formulas

NaCl Dissociates into Ions

Concentration of Vinegar? Knowing that vinegar is an aqueous solution that is 5.00% acetic acid [HC2H3O2(aq)] by mass and has a density of 1.01 g/mL, determine the concentration of vinegar in molarity.