This preview shows pages 1–3. Sign up to view the full content.
This preview has intentionally blurred sections. Sign up to view the full version.
View Full Document
Unformatted text preview: Phys 122 – College physics Midterm 2 Review ! II. Thermodynamics C. Laws of Thermodynamics 1. Systems, states, and processes a. System : quantity of matter enclosed by boundaries or surfaces (real or imaginary; described using macroscopic properties ( T , p , V ) Heat reservoir : a large separate system with unlimited heat capacity; the heat entering or leaving a system comes from or goes to a heat reservoir b. State : specific combination of variables ( T , p , V ) Equation of state : an equation relating the state variables; describes the system c. Process : a change in the system or state variables (heating/cooling) 2. Zeroth Law : Given three objects at temperature T 1 , T 2 , and T 3 , if T 1 = T 2 and T 2 = T 3 , then T 1 = T 3 . 3. First Law : states conservation of energy W U Q + ∆ = ‼ Be careful here with the signs. If heat enters the system, the temperature increases, hence ∆ U is positive. If the system does work, W is positive. If heat leaves the system, the temperature decreases, so ∆ U is negative. If work is done on the system, W is negative. ‼ The work done equals the area under the curve in a pV diagram. 4. Processes for an ideal gas ↓ a. Isothermal process : process happens at constant temperature; therefore, ∆ U = 0. From the first law, we then have Q = W . In a pV diagram: Work in an isothermal process is given by = 1 2 ln V V nRT W isotherm . b. Isobaric process : process occurs at constant pressure In a pV diagram: ! Note that the last page contains a list of symbols used and what they mean. Only the equations and constants will be given on the midterm. ↓ Please refer to the handout on Thermodynamic Processes. M. Ouellette, 9 November 2006 Page 1 of 6 p V 1 2 Work in an isobaric process is given by V p W ∆ = isobaric . c. Isometric process : process takes place at a constant volume: ∆ V = 0; therefore, from the first law we have Q = ∆ U . In a pV diagram: No work is done in an isometric process since there is no area under the curve....
View
Full
Document
This test prep was uploaded on 04/09/2008 for the course PHYS 122 taught by Professor Ouelette during the Fall '07 term at Cal Poly.
 Fall '07
 Ouelette
 Thermodynamics

Click to edit the document details