Gen Chem 3 Week 6 Day 1

What types of motion do the “molecules” have within a SOLID?

vibrational

What types of motion do the “molecules” have within a LIQUID?

vibrational, rotational, translational

What types of motion do the “molecules” have within a GAS?

vibrational, rotational, translational

Entropy Formula

S = kln(w)

S is

ENTROPY

k is

Boltzmann constant

W is

number of microstates

More microstates = more entropy.

Heavier gas, like anything in the He column (more molar mass)

→ higher entropy

More complex molecule

→ higher entropy

Dissolved particles (aq)

→ higher entropy

A solid has

low entropy

A liquid has

medium entropy

A gas has

the HIGHEST entropy

Order of entropy:

Solid < Liquid < Gas

For problems involving ∆𝑆° do

[# moles x j/mol given+ another one if there] - [# moles x j/mol given+ another one if there]

Second Law of Thermodynamics formula

ΔS_univ=ΔS_sys+ΔS_surr

To find surrounding:

ΔS_surr = ΔH_sys/T

For ΔS_sys you look at the

NUMBER OF MOLES IN GAS

If # of moles increase

𝚫𝑺_𝒔𝒚𝒔 > 𝟎

If # of moles decrease

𝚫𝑺_𝒔𝒚𝒔 < 𝟎

For ΔS_surr look @ c

ΔH

If ΔH is positive

ΔS_surr < 0

If ΔH is negative

ΔS_surr > 0