Unit 1: Thermodynamics Lesson 1 & 2

What causes gas pressure?

Molecules colliding with container walls

Avogadro's Number

6.02 x 10^23 particles per mole

What does Temperature measure?

Average kinetic energy of particles

Boltzmann's Constant (kb)

1.38 x 10^-23 J/K

Thermal Equilibrium

When gas particles reach the same temp and avg KE

RMS Speed (v_rms)

Square root of average speed squared (proportional to T)

Ideal Gas Law (using moles)

PV = nRT

Ideal Gas Law (using molecules)

PV = NkbT

Kelvin Temperature formula

K = 273 + Celsius

Gas Constant (R)

8.31 J/(mol*K)

Isothermal Process

Temperature stays constant

Isochoric Process

Volume stays constant

Isobaric Process

Pressure stays constant

Isothermal P-V graph shape

A smooth curve (inverse relationship)

Isochoric P-V graph shape

A vertical line

Isobaric P-V graph shape

A horizontal line

Maxwell Curve Peak

The speed most particles are likely traveling

Maxwell Curve at High Temp

Flatter curve with higher speed range

Internal Energy (U)

Total kinetic energy of all gas particles

Definition of a State Function

Property describing a system at a specific time

Internal Energy depends on…

Temperature and the amount of gas

Formula for Work (W) on a gas

W = -P * Delta V

Work during Expansion

Negative value (Work done BY the gas)

Work during Compression

Positive value (Work done ON the gas)

Work on a P-V graph

The shaded area under the process line

Density (rho) formula

Mass / Volume

Density Greek letter

Rho (p)

Density of water

1000 kg/m^3

Water Displacement use

Finding the volume of irregular objects

Uniform Density

Mass/volume is the same throughout the substance

Pressure (P) formula

Force / Area

SI Unit of Pressure

Pascal (Pa) which is 1 N/m^2

Value of 1 atmosphere (atm)

1.01 x 10^5 Pascals

Ideal Gas collision rule

Collisions are perfectly elastic (no KE lost)

Gauge Pressure

Pressure not including the atmosphere

Absolute Pressure

Gauge Pressure + Atmospheric Pressure

Pascal's Law

Pressure increase in a fluid is uniform throughout

Hydraulic Lift formula

F1/A1 = F2/A2

Pressure location in gas

Exists all throughout (not just at walls)