Surface energy

Question 1

What do the force vectors for liquid-vapor and solid-liquid do when the surface is fully wet?

Answer 1

surface energy for liquid-vapor and solid-liquid point in same direction: Θ = 0 degrees (angle between liquid-vapor and solid-liquid vectors)

Question 2

How do we describe the probability of atoms to arrange themselves into a nucleus with critical radius size?

Answer 2

Boltzmann’s distribution function: C/Co = exp(-G/kT)
Co: # of atoms/vol in parent phase
C: # of atoms in atomic cluster of size r or greater (probability to form nucleus of critical size)

Question 3

surface:

Answer 3

boundary between condensed phase and the gas phase

Question 4

interface:

Answer 4

boundary between two condensed phases

Question 5

interfaces _____ phase transformations

Answer 5

prevent

Question 6

for liquids, surface tension = ________

Answer 6

surface energy

Question 7

What makes the values of surface tension (N/m) and energy (J/m^2) different for a solid surface than from a liquid?

Answer 7

entropy from surface disorder and strain energies

Question 8

crystal habit:

Answer 8

thermodynamically favored macroscopic shape of a material

Question 9

2 ways to minimize surface energy

Answer 9

1. minimize total area exposed

2. expose only lowest energy surfaces