Chapter 6 (section 3) Flashcards
define thermodynamics
The general study of energy and its interconversions
what is the first law of thermodynamics?
the total energy of the universe is constant (energy is neither created nor destroyed)
the internal energy (U) of a system is the sum of…?
the kinetic and potential energies of all the particles that compose the system
define internal energy (U)
The sum of the kinetic and potential energies all of the particles that compose a system
define state function
A function whose value depends only on the state of the system, not on how the system got to that state
what is meant when it is said that internal energy is state function?
It means that the value only depends on the state of the system and not how the system arrived at that state.
What are 4 possible that the state of a chemical system is specified by?
Temperature
Pressure
Concentration
Phase (solid, liquid, or gas)
Since state functions depend only on the state of the system, the value of a change in a state function is always…?
the difference between its final and initial values.
∆ᵣU =…?
∆H final - ∆H initial
or
∆H products - ∆H reactants
If ∆H system < 0 then….?
energy flows out of the system and into the surroundings (∆H surroundings > 0)
If ∆H system > 0 then….?
energy flows into the system out of the surroundings (∆H surroundings < 0)
If the reactants have a higher internal energy than the products, ∆H system is _____ and energy flows….?
negative
out of the system and into the surroundings
If the reactants have a lower internal energy than the products, ∆H system is _____ and energy flows….?
positive
into the system out of the surroundings
A system can exchange energy with is surroundings through _____ and ______
heat (q)
work (w)
The change in internal energy of the system is the sum of the heat transferred and the work done. What is this in equation form?
∆H = q + w
