CHEM 433 – 9/8/11

I. Introductory Topics

A. Mathematical Techniques (REID)- “Differentials” and manipulations thereof

- “Exact” Differentials- “Line” or “Path” Integrals

B. Molecules and Energy (maybe…)

- Definitions & Intro (Ch. 0)

Read: Finish “REID” / Start Chapter “0”

HW: via e-mail TODAY - DUE Th 9/15.

€

dA =∂A

∂b

⎛

⎝ ⎜

⎞

⎠ ⎟h

db+∂A

∂h

⎛

⎝ ⎜

⎞

⎠ ⎟b

dh

From the expression for dA below, derive an expression for:

€

∂A∂h

⎛

⎝ ⎜

⎞

⎠ ⎟b

Is the following differential exact?

€

df = y 2dx + x 2dy

€

dP

dy

⎛

⎝ ⎜

⎞

⎠ ⎟x

= 2y dQ

dx

⎛

⎝ ⎜

⎞

⎠ ⎟y

= 2x NO!!!!

Let’s integrate df along 2 paths from: (1,1) —> (2,2)?

A) (part 1) Along y=1 from (1,1) to (2,1)

(part 2) Along x=2 from (2,1) to (2,2)

B) Along the line x=y€

df = ydx + xdy

€

df1,1

2,2

∫ = ydx + xdy1,1

2,2

∫A1

A2B

(1,1) (2,1)

(2,2)

Basic Definitions re: “Molecules and Energy”

Working Definition of Physical Chemistry: “The study of the physical properties of matter, how these affect chemical change, and the interplay of energy with matter.”

Matter: Atoms and molecules (also p+, n°, e-, quarks?, and all other “stuff” – anything w/ mass).

Substance: A pure distinct form of matter. (i.e. all the atoms/ molecules are the same).

Mole(s): Unit used to specify the amount of a substance (n).

Basic Definitions re: “Molecules and Energy”

Avagadro Constant (NA): 6.02…x1023 mol-1; —> The number of C atoms in exactly 12 g of 12C.

Intensive Properties are independent of n. (P, T, Density…).

Extensive Properties depend on n. (V, mass, entropy…).

Molar Properties: Extensive properties made to be intensive via division by n, i.e. (Xm = X/n).Note: Only intensive properties can be characteristic.

Energy: Capacity to perform work.

(Is energy intensive or extensive?)