1. Macro vs Nanoscale Flashcards
What type of energy is important at the nanoscale?
Thermal energy
Define thermal energy
The kinetic energy of individual molecules, causing constant random motion.
Give the equation for thermal energy
U = thermal energy
k = Boltzmann’s constant
T = temperature
What makes an interaction significant?
If the energy required/generated is greater than the thermal energy (kT).
Microscopic particles move randomly due to the _______ _______ of the neighbouring molecules.
Thermal motion
State the equation for the average mean squared distance diffused by a small particle in liquid in a given time
<x ²> = RMS distance
D = diffusion coefficient
t = time
Give Stokes equation
D = diffusion coefficient
k = Boltzmann’s constant
T = temperature
η = viscosity of the surrounding medium
a = particle radius
Give the Boltzmann equation
P(x) = probability
k = Boltzmann’s constant
What is the Boltzmann equation?
A description of the statistical behaviour of a thermal system that isn’t in equilibrium.
At ‘_____’ distances, interactions between atoms and molecules are strong enough to overcome the effects of thermal motion.
Small
At ‘_____’ distances, interactions between atoms and molecules are too weak to overcome the effects of thermal motion.
Large
How can the strength of an interaction between two molecules be determined?
By comparing the magnitude of the potential energy of the two molecules to the thermal energy.
Give the equation for when an interaction between two molecules is significant
U(x) = potential energy
k = Boltzmann’s constant
T = temperature
Give the equation for when an interaction between two molecules isn’t significant
U(x) = potential energy
k = Boltzmann’s constant
T = temperature
