Units 18-19 Flashcards
What is the constraint on transforming one type of energy into another?
If energy is transformed from one form to another, it cannot be converted back again with perfect efficiency
What does ‘quality’ define?
How efficiently energy can be transformed through work
True or False: Quantity is conserved but quality of energy is not when undergoing a transformation
True
What is the Law of Increasing Disorder
Changes occurring in natural systems always proceed in such a way that the total amount of disorder in the universe is either unchanged or INCREASED.
If total order is increased, the process is irreversible.
What is another name for the Law of Increasing Disorder?
Second law of Thermodynamics
How do you define work?
The energy required to move an object against a force.
True or False: When scientists were examining the steam engine to make it more efficient, they discovered that while work always created energy, heat energy could not be completely converted into work. There was always some leftover.
True
True or False: There is a preferred directionality to processes involving heat.
True
True or False: Heat flows naturally to cold objects without doing work.
True
True or False: Cold air flows naturally to hot objects without doing work.
FALSE
What is an “irreversible” process?
A process that goes in only one direction. Its effects cannot be undone.
Most processes in nature are irreversible.
What is a “reversible” process?
A process that goes both forward and backward at the same time.
Equal ease in both directions.
Relatively RARE in nature.
True or False: Nearly all reversible processes occur only on the molecular level.
True
What conditions determine reversibility?
Temperature and pressure
True or False: There is at least one mechanical process that occurs reversibly.
FALSE.
There are NONE.
Does nature prefer orderliness or disorder?
DISORDER
CHAOS
MUAHAHAHAHAHA!
If two gases are combined, will they ever spontaneously separate again? Or will you have to put in work?
Work.
They will never spontaneously separate.
What is entropy?
A measure of disorder. How much disorder is in a system.
It increases as disorder increases.
How do you calculate entropy?
It’s a mathematical probability of it being in its given state.
What are the two observations of entropy?
- More disordered systems have a higher probability of occurring, and thus have greater entropy.
- In general, increasing the temperature of matter increases its entropy.
What is the effect of entropy on energy?
Increased entropy makes concentrated energy spread out.
What is a “system”?
Everything you put in a box that you want to study.
What are “surroundings?”
Everything outside of the stuff in the box you want to study (the system).
What is the “universe”?
The system + surroundings
What are the two postulates of the Law of Increasing Disorder?
- A reversible process does not change the total amount of disorder in the universe.
- An irreversible process increases the total amount of disorder in the universe.
True or False: If you calculate that a process (that you are predicting can take place or not) will decrease the universe’s entropy… it’s a waste of time because it won’t work.
True
What is macroscopic kinetic energy?
The kinetic energy possessed by moving objects. Big things. Not atomic things.
What is microscopic kinetic energy?
Kinetic energy associated with atomic and molecular motions.
What kind of energy does a stationary, large object have?
Microscopic.
Atoms are moving, object is not
What types of energy are the most ordered?
- Gravitational potential
- Macroscopic kinetic
What type of energy is the LEAST ordered (most disordered)?
Microscopic Kinetic
What is another name for microscopic kinetic energy?
Thermal energy
Rank types of energy from most ordered to least ordered:
- GPE and Macroscopic kinetic
- Nuclear potential
- Electrical (household)
- Chemical potential
- Thermal (microscopic kinetic)
True or False: A form of energy can be converted COMPLETELY into all the forms of energy appearing below it in ranking.
True
What is the price of converting a lower ranking form of energy into a higher one?
Work
True or False: When converting a lower form of energy into a higher one, all the energy is transformed successfully.
FALSE
What is the excess energy that comes from converting a lower form of energy into a higher one?
Based on entropy
Heat usually
What is sunlight?
Nuclear reactions in the Sun
True or False: Sunlight is fairly low quality energy.
False
True or False: A major portion of the chemical energy stored in the plant is discarded as heat when it is broken down (eaten or decays).
True
What is heat death?
The end of all life caused by all mass and energy eventually wearing down and being turned into irreversible thermal energy.
True or False: Every irreversible action ultimately impacts the universe’s quantity of useful energy.
True.
We’re all gonna die.
True or False: Structuring something rather than returning it to its original state is ALSO a form of order.
True
What is the direction of atoms moving in thermal energy?
Random and chaotic
What is the speed of atoms moving in thermal energy?
Random and chaotic