Section Summary

Section Summary

  • Temperature is the quantity measured by a thermometer.
  • Temperature is related to the average kinetic energy of atoms and molecules in a system.
  • Absolute zero is the temperature at which there is no molecular motion.
  • There are three main temperature scales: Celsius, Fahrenheit, and Kelvin.
  • Temperatures on one scale can be converted into temperatures on another scale.
  • Heat is thermal (internal) energy transferred due to a temperature difference.
  • The transfer of heat Q that leads to a change ΔT ΔT in the temperature of a body with mass m is Q=mcΔT Q=mcΔT, where c is the specific heat of the material.
  • Heat is transferred by three different methods: conduction, convection, and radiation.
  • Heat conduction is the transfer of heat between two objects in direct contact with each other.
  • Convection is heat transfer by the movement of mass.
  • Radiation is heat transfer by electromagnetic waves.
  • Most substances have four distinct phases: solid, liquid, gas, and plasma.
  • Gas is the most energetic state and solid is the least.
  • During a phase change, a substance undergoes transition to a higher energy state when heat is added, or to a lower energy state when heat is removed.
  • Heat is added to a substance during melting and vaporization.
  • Latent heat is released by a substance during condensation and freezing.
  • Phase changes occur at fixed temperatures called boiling and freezing (or melting) points for a given substance.