Chem 1910 Midterm 3 Flashcards
What is work?
the process of achieving motion against an opposing force
Systems vs Surroundings
The system is the region of interest while everything else is the surroundings. Together these make up what is referred to as the universe, although it may just be a test tube in some water.
open system
can exchange both matter and energy with surroundings
closed system
cannot exchange matter, but can exchange energy with the surroundings
isolated system
cannot exchange matter nor energy with the surroundings
When is work (w) negative or positive?
w is negative when the system does work on the surroundings and is positive when work is done upon the system
What is energy?
the capacity of some system to do work: more energy = greater capacity for work
Translational Energy
the energy of a molecule or atom due to its movement through space: kinetic energy
rotational energy
energy due to the rotational motion of a molecule: kinetic energy
vibrational energy
the energy stored by a molecule as the oscillation of its atoms relative to one another: kinetic and potential energy
when is q negative or positive
q is negative when a system loses heat and positive when a system gains heat
exothermic
when heat is released into the surroundings
endothermic
when heat is gained in the system
first law of thermodynamics
energy cannot be created or destroyed/the internal energy of an isolated system is constant
deltaU = q + w
state function
a property that depends only on the current state of the system and is independent of how the state was prepared
