Thermodynamics: Chapter Eight
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Thermodynamics: Chapter Eight
What is energy?
the capacity to do work, or supply heat
What is the formula for energy?
Delta Energy= work + heat
What is kinetic energy?
energy of motion
What is potential energy?
What is thermal energy?
the kinetic energy of molecular motion (translational, rotational, and vibrational)
Thermal energy is proportional to __
the temperature in degrees Kelvin
What is heat?
the amount of thermal energy transferred between two objects at different temperatures
In an experiemnt: Reactants and products are th e__; everything else is the __.
Energy flow from the system to the surroundings has a __ sign. (__)
loss of energy
Energy flow from surroundings to the system has a __ (__)
gain of energy
matter or energy can be exchanged
only energy can be lost or gained
no matter or energy is exchanged
What is the law of conservation of energy?
The energy of an __ system must be __>
energy cannot be created or destroyed
The energy change in a system equals __
the work done on the system plus the heat added
DeltaE= q+w, where q= heat and w= work
A reaction that combines something with oxygen is called?
What is pressure? What is it measured by?
Force per unit area
Pascals or 1 atmospheric unit (atm)
What is work?
force that produces an object's movement, times the distance moved
Work = Force x Distance
Work done by a system is __.
Work done on a ssystem is __.
I L atm= __ Joules?
What is a state function?
a function or property whose value depends only on the present state (condition) of the system
The change in a __ is __ when the system returns to its original condition.
For __, the change is not __ if the path returns to its original condition.
The amount of heat exchanged between the system and the surroundigns is given the symbol __.
What is the equation for it?
At constant value (DeltaV=0): q
At constant pressure: q
q= DeltaE + PDeltaV
What is enthalpy?
DeltaH is __
a state function whose value depends only on the current state of the system, not on the path taken to arrive at that state
enthalpy change or heat of reaction (at constant pressure)
What is the Thermodynamic Standard State?
most stable form of a substance at 1 atm pressure and at a specified temperature, usually 25 degrees C; 1 M concentration for all substances in solution
What is enthalpy of Fusion DeltaH
the amount of heat necessary to melt a substance without changing its temperature
What is enthalpy of vaporization (DeltaH
The amount of heat required to vaporize a substance without changing its temperature
What is enthalpy of sublimation (DeltaH
the amount of heat required to convert a substance from a solid to a gaas without going through a liquid phase
Enthalpies of chemical change are often called __.
heats of reaction (DeltaH
What is endothermic?
: heat flows into the system from the surroundings and DeltaH has a positive sign
: heat flows out of the system into the surroundings and DeltaH has a negative sign
What does reversing a reaction do to DeltaH?
changes the sign (multiply by -1)