Ch 7 Lec 1 - Thermochemistry Flashcards
part of the universe chosen to be studied (large or small)
system
part of the universe outside the system but with which the system interacts
surroundings
system that freely interacts with surroundings and can exchange both matter and energy with surroundings
open system
system that can exchange energy but not matter with the surroundings
closed system
system that does not interact at all with the surroundings
isolated system
the capacity to do work
energy
done when a force acts on an object through a distance
work
energy of a moving object
kinetic energy
stored energy or energy resulting from a condition, position, or composition (associated with forces of attraction or repulsion)
potential energy
kinetic energy that is associated with random molecular motion; proportional to the temperature of a system
thermal energy
the transfer of thermal energy or energy transfer between a system and its surroundings as a result of a temperature difference
heat
molecules of the warm body lose KE through collisions to the colder body which causes a blank flow
heat
heat flows until the average blanks are the same
kinetic energies
si unit of heat
joules
other units of heat
calories (cal), kilocalories (Cal)
quantity of heat required to change the temperature of a substance by 1 degree Celsius
heat capacity
if the system is one mole of a substance (J/mol)
molar heat capacity
quantity of heat required to change the temp of 1 gram of a substance by 1 degree Celsius
specific heat capacity
in interactions between a system and its surroundings, the total energy remains constant
law of conservation of energy
energy associated with chemical bonds and intermolecular attractions
chemical energy
quantity of heat exchanged between a system and its surroundings when a chemical reaction takes place (at constant temperature)
heat of reaction
reaction that gives off heat to the surroundings and produces a temperature change in surroundings (in isolated system, the temperature of system increases) (negative)
exothermic
reaction that gains heat from the surroundings (isolated system produces a temp decrease) (positive)
endothermic reaction
used as a rxn vessel to determine qrxn
calorimeter
a bomb calorimeter is a blank system
isolated
when combustion occurs, chemical energy is converted to thermal energy and the temperature of the water blanks in a bomb calorimeter
increases
