## Lecture 17: Liquids, Gases, and Phase Transitions

October 26, 2017

• Study: Fig 7.1; Ex 1; Eq 7.23; Exs 4, 6; Eq 7.38; Exs 7, 8.

### Objectives

• (Continuing objective) Be able to relate concepts of thermodynamics and statistical mechanics to “everyday” situations and to discuss various applications of the concepts to practical problems in various fields of science, medicine and engineering.
• Give a molecular description of a solid, liquid and a gas; i.e., be able to explain how the motion of individual molecules and the patterns that they form differ between solids, liquids and gases.
• Describe qualitatively why melting and vaporization phase transitions occur, and what their associated latent heats are. Use latent heat of fusion or vaporization to calculate the heat released or absorbed during a phase transition.
• Relate thermal kinetic energy, thermal speed, and temperature for a solid, liquid, or gas.
• Describe the properties of monatomic and diatomic ideal gases, including their molar specific heat and speed of sound.
• Relate pressure, volume, temperature, and number of molecules or moles, or changes in the quantities, using the ideal gas law.

### Homework

• Friday's Assigned Problems: A47, A76; Supp CH 7: 1, 2, 3, 4, 5, 12, 13, 15
• Monday's Hand-In Problems: A48; Supp CH 6: 12, 13, 14, 16, 18; Supp CH 7: 8, 9, 10, 14

### Videos of example problems

To see the problem statement, click on the link below. To play the video example, click on the underlined words "Video Demonstration" near the top of the page with the problem statement.
• Video Example #1: Estimate melting temperature and latent heat for nickel.
• Video Example #2: Another example with Ideal Gas Law. Note that in the final case, the water is boiling. ans: 1.71

### Drinking bird reference of the day

"This is the greatest invention in the world!" -- Homer Simpson

### Pre-Class Entertainment

• Natural Blues, by Moby
• Norwegian Wood, by the Beatles
• Not Fade Away, by Buddy Holly and the Crickets
• No Rain, by Blind Melon
• No Roots, by Alice Merton
• Out in the Street, by Bruce Springsteen and the E Street Band
• Outa Space, by Billy Preston