# Basic Thermochemistry and Units for Measuring Heat

This article discusses basic principles of thermochemistry and the units used to measure heat. It explains that the Joule is the SI system unit for measuring heat, while the calorie is

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## About Basic Thermochemistry and Units for Measuring Heat

PowerPoint presentation about 'Basic Thermochemistry and Units for Measuring Heat'. This presentation describes the topic on This article discusses basic principles of thermochemistry and the units used to measure heat. It explains that the Joule is the SI system unit for measuring heat, while the calorie is. The key topics included in this slideshow are . Download this presentation absolutely free.

## Presentation Transcript

Slide1Basic Thermochemistry Basic  Thermochemistry Courtesy of lab-initio.com

Slide2CA Standards CA  Standards

Slide3Units for  Measuring  Heat Units  for  Measuring  Heat Joule The  Joule  is the SI system unit for measuring heat: calorie The  calorie  is the heat required to raise the temperature of 1 gram of water by 1 Celsius degree

Slide4Heat (Enthalpy)  Change,  Δ H Heat  (Enthalpy)  Change,  Δ H Definition:   The  amount  of  heat  energy released  or  absorbed  during  a  process. Definition:   The  amount  of  heat  energy released  or  absorbed  during  a  process. Energy Energy Energy  is  the  capacity  to  do  work Energy  is  the  capacity  to  do  work , and can take many forms   Potential energy is stored energy or the energy of position   Kinetic energy is the energy of motion   Thermal energy (heat) is an outward manifestation of movement at the atomic level

Slide5CalorimetryCalorimetry calorimeter The amount of heat absorbed or released during a physical or chemical change can be  measured, usually by the change in temperature of a known quantity of water in a  calorimeter .

Slide6Exothermic Processes Exothermic  Processes Reactants     Products  +  energy Reactants     Products  +  energy Processes  in  which  energy  is  released  as  it proceeds,  and  surroundings  become  warmer Processes  in  which  energy  is  released  as  it proceeds,  and  surroundings  become  warmer

Slide7Endothermic Processes Endothermic  Processes Reactants  +  energy     Products Reactants  +  energy     Products Processes  in  which  energy  is  absorbed  as  it proceeds,  and  surroundings  become  colder Processes  in  which  energy  is  absorbed  as  it proceeds,  and  surroundings  become  colder

Slide8Water phase  changes Water  phase  changes Temperature remains __________ during a phase change. constant

Slide9Phase Change  Diagram Phase  Change  Diagram Processes  occur  by  addition  of  energy   Processes  occur  by  addition  of  energy      Processes  occur  by  removal  of  energy    Processes  occur  by  removal  of  energy

Slide10Phase Diagram Phase  Diagram    Represents  phases  as  a  function  of temperature  and  pressure.    Represents  phases  as  a  function  of temperature  and  pressure.    Critical  temperature:   temperature  above which  the  vapor  can  not  be  liquefied.    Critical  temperature:   temperature  above which  the  vapor  can  not  be  liquefied.    Critical  pressure:   pressure  required  to liquefy  AT   the  critical  temperature.    Critical  pressure:   pressure  required  to liquefy  AT   the  critical  temperature.    Critical  point:   critical  temperature  and pressure  (for  water,  T c   =  374°C  and  218 atm).    Critical  point:   critical  temperature  and pressure  (for  water,  T c   =  374°C  and  218 atm).