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
What is efficiency?
The percentage of energy that is converted into USEFUL energy.
What is diffusion?
The spreading of something through another material.
Like ink diffusing through water (mixing and spreading with it).
True or False: Diffusion is always uniform.
True
It seems to be
When do we experience the direction of time? When we are in equilibrium or disorder?
Disorder.
That is the only way we experience time in a certain direction (forwards only, not backwards or all at once).
Why is hot air more disordered?
Because heat causes molecules to speed up, so they move more randomly.
Which type of matter has the highest amount of disorder?
Gas
Does the law of increasing disorder refer to the disorder of the universe or the system?
UNIVERSE in total.
What is the culprit of the world’s energy crisis?
The Law of Increasing disorder
Energy deficiency
Pure substance
A substance with a regular, repeating building block that gives it a defined, fixed chemical composition. Unchanging.
Element
A substance composed entirely of atoms of the same type.
True or False: A pure substance can be one type of atom or many different types.
True
Compound
A substance with more than one type of atom.
Which are more common in nature? Compounds or elements?
Compounds
Mixtures
Substances physically mixed together with LITTLE OR NO BONDING between molecules.
What do you call mixtures of solids?
Blends or composites
Blend or Composite
More than one type of matter that has been put together in close proximity but not chemically mixed together.
What’s an example of a composite mixture?
Salt and pepper mixed together in a bowl.
Solutions
Mixtures of pure substances. One of them has to be a liquid, and the other component(s) are completely dissolved in that liquid.
Alloy
A solid solution of metals. One or more metals dissolved in each other and then solidified.
True or False: Pure metals are hard and enduring.
False
True or False: Pure metals are soft and malleable.
True
True or False: The properties of mixtures are derived from the pure substances that make them up.
True
Atomic matter
Matter that exists in the solid, liquid, and gaseous states as single atoms.
Molecular matter
Matter that exists as molecules in the solid, liquid, and gaseous states
Which members of the periodic table are atomic matter?
8a noble gases
Network or Extended-bonding substances
Substances in which every atom or ion interacts STRONGLY with MANY NEIGHBORS.
It’s an extended network of atoms or ions.
True or False: Distinct molecules or ion pairs do not exist in network substances
True
What is an example of a molecular substance?
Water
What does it mean that water is molecular matter?
That in all three states (excluding plasma) the molecules H20 remain bound tightly together.
Examples of network matter
Magnesium and aluminum
Sodium and chlorine
Silicon and oxygen
What is the matter classification type based on?
How atoms join together
True or False: Atomic substances have very low melting and boiling points
True
True or False: Network substances have extraordinarily high melting and boiling points.
True
Chemical bond
The attractive force between nuclei and electrons that hold atoms / matter types together.
What are the three types of bonds?
- Metallic
- Ionic
- Covalent
What type of matter do metallic and ionic bonds hold together?
Network matter
What type of bond holds molecular matter together?
Covalent
What is a diatomic molecule?
It has two atoms of the same kind of element.
Hydrogen, nitrogen examples
Connectivity
The details of how atoms connect to one another in molecules or structures.
The “sticks” of the diagrams of molecules
Double bond
Atoms are connected by 2 sticks.
Covalent bond involving two pairs of electrons.
So four electrons total, two per bond.
Triple bond
A covalent bond involving three pairs of electrons shared between the two bound atoms.
Hydrocarbons
Chemical compounds between the elements of carbon and hydrogen. It’s a group/family.
Hydrocarbon molecules
Molecules that contain only carbon and hydrogen atoms.
Organic acid
A molecule that contains the fragment CO2H attached to another carbon atom
Amine group
The grouping of NH2 attached to a carbon atom
What determines the bonding geometry of the compound?
The number of bonds that an atom can form.
Crystals
A solid with a regular repeating arrangement of molecules or ions
What is “spectroscopy”?
Techniques used to identify elements that makeup molecules. Examines how they bond together and measures the energy of those bonds.
What is optical spectroscopy?
The technique used to study emission and absorption lines from different atom and molecules.
True or False: When atoms bond together, individual electron orbital energies are altered.
True
What is electronic spectroscopy?
Looking at the color of the compound (which is a reflection of the molecules) to determine what it’s made from.
Molecules emit unique spectra just like atoms (optical).
What are electron bonds compared to? What toy?
A slinky
Or a mattress spring
What is caused by bonds flexing, compressing, or expanding?
Vibrations.
What do bond vibrations cause?
Light in the infrared region.
Changes the emitted spectra of light in this region.
On an infrared spectra graph, what does it mean when the line dips downward?
That the substance absorbs light more strongly at that frequency.
What is a mass spectrometer?
An instrument that detects and measures the fragments of a destructed molecule after it has been blasted apart into ionized pieces.
This allows scientists to see the mass of each individual type.
What is crystallography?
Diffraction and interference patterns from electron beams, x-rays, or something else can be used to discover the spacing and sizes of the gaps between atoms in crystals.
This helps them determine the structure of the crystal.
Atomic mass unit (AMU)
A unit to measure mass of very small amounts. 1 amu = 1.66 × 10−27
Salt
At least one metal and nonmetal bonded together to form network matter.
True or False: As long as a compound has the right number of atoms of each type, it will react in the right way.
Why or why not?
FALSE
The organization of the atoms in the structure matters.
True or False: The structure or arrangement of molecules matters.
True
True or False: If the formula is the same but the structure is different, you have different substances.
TRUE
True or False: A triple bond is basically equivalent to three single bonds.
True
Are double bonds stronger than single bonds?
yes
Are triple bonds stronger than double bonds?
yes
How is vibrational spectrometry measured?
The amount of electromagnetic radiation that’s absorbed by a molecule.
Measured as the frequency
What is another name for vibrational spectrometry?
IR spectra
What is used to figure out a “fingerprint” for the chemical compound?
Spectrometry!
Various techniques
