Thermodynamics

15A Temperature

• Temperature: the measure of the hotness or coldness of a substance; proportional to the average kinetic energy of the particles within the substance

• Thermometric Property: any property that changes predictably with changes in temperature

• Thermal Expansion: the property of many materials to increase in volume when heated and contract when cooled

• Temperature Scales

  • Fahrenheit

  • Celsius

  • Kelvin

15B Heat

• Heat: movement of thermal energy from an area of higher temperature to one of lower temperature

• Energy Transfer

  • Conduction: movement of electric charge or thermal energy through an object or from object to object through direct contact

  • Convection: movement of thermal energy as fluids move

  • Radiation: movement o energy in the form of electromagnetic waves

• Thermal Conductor: a material through which thermal energy moves easily

• Thermal Insulator: a material through which thermal energy does not easily move

• Measuring Heat

  • Specific heat: the energy required to raise the temperature of 1 g of a substance 1 degree Celsius

  • Calorimeter: a device that enables scientists to measure the thermal energy transferred in reactions and between systems

• Energy Transfer By Heating

  • Heating ice

  • Melting ice

  • Heating water

  • Vaporizing water

  • Heating steam

15C Thermodynamics

• Thermodynamics: the study of thermal energy and heat and how they relate to work and other forms of energy

• Caloric Theory: the now-obsolete theory that stated that heat was an invisible self-repelling fluid

• Laws of Thermodynamics:

  • First Law of Thermodynamics: the law that states that energy cannot be created or destroyed but only transferred between objects or transformed; also known as law of conservation of energy

  • Second Law of Thermodynamics: the law that states that energy can flow from a colder object to a warmer object only if something does work

  • Third Law of Thermodynamics: the law that states that entropy would be at its minimum value at absolute zero. Therefore, absolute zero can never be achieved