Thermodynamics Review (DW)

Vocabulary

• Temperature
• Heat
• Internal Energy
• Related to the average translational kinetic energy of a particle in a sample
• The energy transferred between two objects due to a temperature difference
• The total of all kinetic energy in a sample (translational, rotational, and vibrational)

Equations

• Raising the temperature of a substance
• Phase change for melting / freezing
• Phase change for vaporisation / condensation
• q = mc∆T = mc(Tf - Ti)
• q = mLf
• q = mLv

Heating Curve for Water

• 
• Caption: Heating curve for water
• Temperature rise = increase in kinetic energy
• Phase change = increase in potential energy

Calorimetry: T1 + T2 = T3

• Two substances have different temperatures; find the final temperature
• mc(Tf - Ti1) + mc(Tf - Ti2) = 0
• Solve for Tf

Calorimetry: Phase Change

• Ice and hot aluminum brought to equilibrium
• 1) Find heat needed to get ice to 0.0 °C (Ti to 0.0°C)
• 2) Find heat needed to get Al to 0.0°C
• Check: Is 2 ans > 1 ans?
• 3) Find heat needed to melt ice
• Check: 1 ans + 3 ans
• 4) Final phase = warm water
• 5) Q1 + Q3 + Q4 + Qal = 0
• Solve for Tf

Heat Transfer Types

• Conduction
• Convection
• Radiation
• Solids
• Fluids
• Empty space & some matter

Conduction

• Equation (conduct the cattle)
• k units
• k
• L
• q/t = (kA∆T)/L
• N/ s•°C
• Thermal conductivity constant
• width

Conduction Equation Comparison

• Given
• Substitute
• Plug in from given
• Divide. They both have modifications, so placement doesn't matter. (NO)
• L doubled, d tripled
• A = πd/2
• E1 = kπ(3d/2)∆T/L
• E2 = kπ(d/2)∆T/2L
• E1/E2 *If only E1 was modified, it would be on the bottom; new/old*

Conduction with Kinetic Energy

• Problem
• Find
• Kinetic energy = heat
• Cancel m, solve for ∆T; add to original temperature
• Ball thrown at insulator
• Final temperature
• .5mv^2 = mc∆T
• ∆T = .5mv^2/c

Thermal Expansion

• Equation
• α
• Metal ring expands
• ∆L = α Lo∆T
• Coefficient of linear expansion
• Hole and outside grow

Slide 11