Temperature
A measure of the average kinetic energy of the particles in something. The SI scale is kelvin: K = degrees Celsius + 273.15.
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Analogy
Like the average speed of dancers in a crowd.
Example
T(K) = T(C) + 273.1537 C = 310.15 K0 C = 273.15 K
In practice
Absolute zero is 0 K, or -273.15 degrees Celsius. Body temperature of 37 degrees Celsius is 310 K.
Practice
Flashcards
- What is absolute zero in Celsius?-273.15 degrees Celsius (0 K).
- How is temperature linked to molecule energy?Average kinetic energy per molecule is 3/2 k T.
Interview questions
- Explain why heat flows from hot to cold and never the other way by itself.
- Second law
- Entropy of isolated system never decreases
- Heat flowing cold to hot would lower total entropy
Questions people ask
What is the difference between heat and temperature?
Temperature is a measure of the average kinetic energy of particles. Heat is energy that moves from a hot object to a colder one because of a temperature difference. A bath of lukewarm water holds more heat than a hot match, though the match has a higher temperature.
Why do we use kelvin in gas law problems?
The gas law needs a scale that starts at true zero. At 0 K the particles have the lowest possible energy. Celsius has zero at the freezing point of water, which would give nonsense such as negative volumes. Always add 273.15 to Celsius before using PV = nRT.