1 / 6

Chapter 19 Heat and the First Law of Thermodynamics

Chapter 19 Heat and the First Law of Thermodynamics. 19-5 Latent Heat. Energy is required for a material to change phase , even though its temperature is not changing. Latent heat is the heat (energy) required to change 1kg of substance from solid to liquid. 19-5 Latent Heat.

ursulaj
Download Presentation

Chapter 19 Heat and the First Law of Thermodynamics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Chapter 19Heat and the First Law of Thermodynamics

  2. 19-5 Latent Heat • Energy is required for a material to change phase, even though its temperature is not changing. • Latent heat is the heat (energy) required to change 1kg of substance from solid to liquid

  3. 19-5 Latent Heat The total heat required for a phase change depends on the total mass and the latent heat:

  4. 19-5 Latent Heat Heat of fusion, LF: heat required to change 1.0 kg of material from solid to liquid Heat of vaporization, LV: heat required to change 1.0 kg of material from liquid to vapor

  5. 19-5 Latent Heat The latent heat of vaporization is relevant for evaporation as well as boiling. The heat of vaporization of water rises slightly as the temperature decreases. On a molecular level, the heat added during a change of state does not increase the kinetic energy of individual molecules, but rather break the close bonds between them so the next phase can occur.

  6. 19-5 Latent Heat Example 19-6: Determining a latent heat. The specific heat of liquid mercury is 140 J/kg·°C. When 1.0 kg of solid mercury at its melting point of -39°C is placed in a 0.50-kg aluminum calorimeter filled with 1.2 kg of water at 20.0°C, the mercury melts and the final temperature of the combination is found to be 16.5°C. What is the heat of fusion of mercury in J/kg?

More Related