1. As always… Lon-Capa assignments Lecture videos Textbook Read
Do text homework

2. Office Hours 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

3. To Improve: The Obvious
Lecture
Attend.
Textbook
Read it and do the homework.
Videos
Watch them.
Lon-Capa
Do the assignments.
HW#1: 97%
HW#5: 84%

4. To Improve: The Less Obvious
Lecture
Be active (come prepared, ask questions).
Textbook
Read critically, before lecture (take notes, ask questions).
Videos
Watch critically, before lecture (take notes, ask questions).
Lon-Capa
Do the assignments as you learn about the material.

5. To Improve: The Not Obvious
Change how you view homework.
It is not just something to be over with.
Change how you view studying.
You are currently studying for the second exam whether you believe it or not.
Change how you view learning.
Do it for understanding not for points (and you’ll earn both!).
Manage your time wisely.
3 am Lon-Capa?

6. Grades 150 points are a given! Think of course as out of 1000 points
450 exam points
400 final exam points
100 Lon-Capa homework points
50 discussion/text homework points
150 points are a given!
(or should be!)

7. NH4NO3(s)  NH4+(aq) + NO3–(aq) ΔH = 25.7 kJ
Clicker Question
A g sample of NH4NO3(s) is dissolved in mL of water with both substances initially at room temperature (24.7°C). Calculate the final temperature of the solution. You may make the following assumptions: no heat loss to the surroundings; the specific heat capacity of the solution is 4.18 J/g°C; and the density of the solution is 1.00 g/mL.
NH4NO3(s)  NH4+(aq) + NO3–(aq) ΔH = 25.7 kJ
a) 17.0°C
b) 17.7°C
c) 31.7°C
d) 32.4°C
e) I cannot get any of these answers.

8. Bomb Calorimeter (constant V)

9. Determining Hrxn
Since H = qp, determine the heat given off or required at constant pressure by measuring temperatures. This is termed calorimetry.
Since energy is conserved, we can often determine Hrxn for one reaction given values of Hrxn for others. Uses the principle in Hess’s Law.
Use standard enthalpies of formations for reactants and products (we have tables of these).

10. Hess’s Law Due to first law and H being a state function.
If a reaction is reversed, the sign of H is also reversed
The magnitude of ΔH is directly proportional to the quantities of reactants and products in a reaction.
That is, if the coefficients in a balanced equation are multiplied by an integer, the value of H is multiplied by the same integer.