Final Exam Flashcards
What is a “valence shell”?
The outer shell of electrons in an atom, where it meets and combines with other atoms.
The atomic number of Magnesium (Mg) is 12. Tell how many protons, neutrons and
electrons there are in one atom of 25Mg++. How many electrons are in that atom’s
valence shell? Explain your reasoning.
Since the atomic number is 12, that is the number of protons. Since the atomic mass is 25, which is equal
to the total number of neutrons and protons, there must be 25-12 = 13 neutrons in this isotope. An
electrically neutral atom has the same number of protons as electrons. Since this atom is a double-positive
ion, it must have two more protons than electrons, and therefore has only 10 electrons. Finally, since there
the first two electrons fill the first shell, there are eight to fill the outer, valence shell.
What are the three major ways atoms bond to form molecules? Give a brief explanation
of each.
In an IONIC bond, atoms that lose or gain electrons to have full valence shells will then become ions, and
may stick together electrostatically. In COVALENT bonds, two or more atoms fill their valence shells by
sharing electrons. A special type of this is the METALLIC bond, in which the electrons are passed around
and shared by all the atoms in the material.
Explain what an isotope is, and what an ion is.
Atoms of the same element which differ in the number of neutrons they have are known as “isotopes” of
that element. “Ions” are atoms which have an unequal number of protons and electrons.
What is a “half-life”?
It is the empirically determined length of time it takes for half of the population of something to disappear
or transform.
List the four fundamental forces, from weakest to strongest.
Gravity, Weak Force, Electromagnetic Force, Strong Force
What is a star?
A large ball of plasma (or gas) that radiates energy into space through fusion reactions powered by gravity
What is going to happen to our Sun?
It will complete its hydrogen-burning phase in a few billion years, enter into a “helium-burning” phase,
turn into a Red Giant, and then into a White Dwarf. Eventually, billions more years later, it will cool into a
chunk of mostly carbon.
Briefly describe the Milky Way galaxy
It is a spiral galaxy consisting of about 100 billion stars, about 100,000 ly across, with a central bulge
known as the nucleus, and bright regions (spiral arms) where new stars are being formed.
List at least three facts that serve as evidence for the Big Bang.
- Universal expansion, 2. Cosmic microwave background radiation, 3. Abundance of light elements, 4.
Lack of antimatter. 5. Hubble’s constant, 6. The darkness of the night sky (Olber’s paradox).
According to current science, what is the likely fate of the universe?
Even counting dark matter, we estimate that only about 20% of the mass necessary to slow down the
expansion of the universe exists. In fact, recent (1999) observations indicate that the expansion might
actually be speeding up. We probably live in an “open” universe, which means it will expand forever,
cooling as it does, eventually to absolute zero. Sometimes called “Heat Death.”
What is the Nebular Hypothesis, and what evidence exists for it?
About 4.5 billion years ago, a large, rotating cloud of gas coalesced under gravitational attraction to form
small chunks of material called planetesimals. These collided with each other to produce larger and larger
objects. Most of the mass, however, coalesced in the center to produce the Sun. Evidence for this is (1) the
difference between the inner (terrestrial) planets, which are small rocky worlds and the outer (Jovian)
planets, which are large balls of frozen gas, essentially the same as the original nebular medium, (2) the
planets revolve around the sun in the same direction as its rotation (3) most of the planets rotate on their
axes in the same direction as the sun’s rotation, (4) the plane of revolution of most of the planets is within
about 5° of the ecliptic. It’s hard to believe that all this is just a coincidence!
Explain the three basic types of plate boundaries
(1) Divergent, in which two plates are moving away from each other, (2) Convergent, in which they are
pressing against each other, and (3) Transform, in which they are scraping alongside each other.
Explain what S and P waves are and tell why the difference between them matters to
seismologists.
These are some of the waves that are produced by earthquakes. P waves are “primary” waves, formed from
the Earth shaking up and down. They are longitudinal in nature, and therefore can travel through the
Earth’s liquid outer core. They are faster than S waves, and so are the first to arrive at a detection station.
S waves (“secondary”) are caused by the surface moving back and forth, are transverse, and cannot travel
through the outer core. They arrive later and have magnitudes different from the P waves. These features
allow for the calculation of the earthquake’s magnitude and point of origin (“epicenter”).
Give the names of at least six of Earth’s tectonic plates.
African Anatolian Antarctic Arabian Australian-Indian Caribbean Cocos Eurasian Hellenic Iranian Juan de Fuca Nazca North American Pacific Philippine Scotia South American
Explain the “First Principle of Science”
It may be stated as “There exists an objective reality,” and means essentially that at least some of the
features of reality are as they are independently of what we might believe. It deserves primacy of place
because, unless science and scientists believe that, there can be no investigation into the physical world, no
learning.
Write the equation for a graphed line, and explain its terms.
Y=mx +b. Y is the value of the dependent variable (vertical axis), x the value of the independent variable
(horizontal axis), m is the slope of the line (rise/run or dy/dx), indicating the rate of change, and b is the “yintercept” where the line crosses the y-axis (x=0).
What are the three different ways in which heat is transferred?
- conduction
- convection
- radiation
Explain the difference between longitudinal waves and transverse waves, and give an
example of each.
In T-waves, the motion of the wave itself is different from (perpendicular to) the motion of the medium in
which the wave moves. For example, waves in water move across the surface of the water, while the water
itself merely moves up and down.
In L-waves, the wave moves in the same direction as the medium through which it moves. Sound waves,
for example, are created by moving air molecules back and forth, which then collide with neighboring
molecules, inducing them to continue the process.
What features are shared by all electromagnetic waves? In what ways might two such
waves differ?
They all travel at the speed of light and the need no medium through which to travel. They can differ
according to wavelength and frequency (and therefore energy).
What is the difference between “special” relativity theory and “general” relativity
theory?
Special relativity deals with observers who are not accelerating with respect to each other, while general
relativity deals with any frame of reference whatsoever
What, according to special relativity, happens to my alarm clock when I throw it across my room in
the morning? Will I be able to observe these effects?
Its mass increases, it gets shorter in the direction it is traveling, and it keeps time more
slowly. None of these effects are observable unless the object is traveling at “relativistic”
speeds, i.e., speeds that are a significant fraction of the speed of light, so I won’t notice
anything. I’ll feel a lot better, though.
What is “wave-particle duality”?
Every quantum particle (atom-sized or smaller) exhibits qualities of waves or particles, depending upon
how they are observed.
What two important features of “chemistry” is it important to know?
- Chemistry takes place in the outer (“valence”) shells of atoms.
- A significant portion of the characteristics of the resulting molecule is determined by its physical shape
What causes the surface tension of water, and why?
It is caused by a hydrogen bond. When two H atoms covalently bond with one O, they are offset on one
side at about a 135 degree angle – making the molecule look like “Mickey Mouse” ears. The shared
electrons spend more time going around the O end of the molecule, since it’s so much bigger, and therefore
that end takes on a net negative polarity, with the H end being positively charged. Two H2O molecules can
then chain together with a weak electrostatic link.
What is a “bit”?
The term comes from “binary digit,” and is the basic unit of information in computer processing. It can
represent anything that can only be in one of two states (e.g., “off” or “on,” “yes” or “no” and so forth).
What are the four classic states of matter, and how are they defined?
A gas expands to fill its container.
A liquid maintains a constant volume, but take the shape of its container.
A solid maintains both its volume and its shape.
A plasma is an ionized gas with can be contained in a magnetic field.
Explain the difference between mass and weight.
Mass is the amount of material an object has – it is a measure of its inertia, of how much force it would
take to change its momentum. Weight is the amount of force exerted on a particular object’s mass by the
gravitational attraction of another (generally much larger) object on which it may be placed.
Explain the three components of any observation or measurement.
M = V + B + e; a measurement is a combination of the true value of that which is being measured, plus bias
in the measuring method, plus chance error. Bias always goes in the same direction, but chance error
averages to zero, by definition.
What must we be able to show in order to say that “A causes B”?
- That A comes before B in time
- That A correlates with B
- That there is some mechanism by which A can “connect” to B
- That we have discounted any possible C which actually causes them both
What are speed, velocity, and acceleration?
Speed is distance divided by time, such as “miles per hour.” Velocity is speed plus location or direction.
Acceleration is any change in velocity.
Would it take as much energy for you to climb ten feet up a ladder as it would for you to
jump ten feet straight up into the air? Why or why not?
It would take the same amount of energy, but the second action would require more power, which is
work/time.
What is the difference between “heat” and “temperature”? Does a pint of boiling water
at 100 oC contain as much heat as a quart of boiling water at 100 oC?
Heat is a form of energy that flows from a warmer object to a cooler object. It is a measure of the quantity
of atomic kinetic energy contained in an object, often measured in calories. Temperature is a relative term
and says how vigorously the atoms in the substance are moving. A quart of boiling water therefore has the
same temperature as a pint of boiling water, but twice as much heat (because there is twice as much water).
State Coulomb’s Law, in your own words.
The force between any two electrically charged objects is proportional to the product of their charges and
inversely proportional to the square of the distance between them.
Give an example of a situation in which entropy increases.
Any will do, provided that it is an example of a situation in which order has decreased. Bedrooms tend to
become messier, bodies age and die, ice melts, and so on.
What is the difference between AC and DC current? What kind is produced by a
battery?
Alternating Current is produced by a conductor spinning through a magnetic field. The electrons in the
conductor move through it first in one direction, then reverse – twice for each spin cycle. Electrons in
Direct Current move in one direction only, from the “negative” side of the source to the “positive” side.
This is the kind produced by a battery.
Explain why “magnetic monopoles” do not exist.
Magnetism is produced by all moving electrical charges. An electron in motion around a proton in an atom
constitutes a current, just like in a circuit in an electromagnet. Because of this, even if you break a magnet
apart down to a single atom, you will still have a current loop and therefore a dipolar magnetic field.
A race car completes a 2-mile oval track in 58 seconds. Did the car accelerate during
those 58 seconds? Why or why not?
Yes, it did accelerate, even if it ran at a constant speed, because it turned around the oval track, and a
change in direction is also a change in velocity, which is what acceleration is.
Explain the concept of a “trophic level.” At which trophic level are omnivores?
Living things that get their energy from the same source are said to belong to the same “trophic level.”
Plants, which use photosynthesis, are at the first level, herbivores at the second, and carnivores at the third.
Carnivores that eat other carnivores are at the fourth level. Omnivores vary in level, depending on what
they eat, and “decomposers” are in a separate category.
acid rain
phenomenon that occurs when nitrogen and sulfur compounds in the air interact with water to form tiny droplets of nitric and sulfuric acid
air pollution
serious environmental problem, with immediate consequences for urban residents, from the emission of nox compounds, sulfur dioxide, and hydrocarbons in the atmosphere
angiosperms
the class of vascular plants that flower
arthropods
all invertebrate animals with segmented bodies and jointed limbs. most successful phylum in the animal kingdom in terms of numbers of species and total mass; includes insects, crustaceans, and spiders
atmospheric cycle
the circulation of gas near earths surface, which includes the short-term variations of weather and the long-term variations of climate
animals
multi-celled organisms that get their energy by eating other organisms; one of five kingdoms in the modern Linnaean classification
biology
branch of science devoted to the study of living systems
cell
a complex chemical system with the ability to duplicate itself; the fundamental unit of life
biome
a large naturally occurring community of flora and fauna occupying a major habitat, e.g. forest or tundra.
cell membrane
a structure, formed from bilayers of lipids, that separates the inside of the cell from the outside, or separates one part of a cell from another
climate
the average weather conditions of a place over a period of years
current
a river of moving water, found in each of the ocean basins
cell wall
a solid framework made from cellulose molecules and other strong polymers, by which plants cells are separated from one another
chloroplasts
the main energy transformation organelles in plant cells; places where the molecules of chlorophyll are found and photosynthesis occurs
domains
region in magnetic material where neighboring atoms line up with each other to give a strong magnetic field
ecology
the branch of science that studies interactions among organisms as well as the interactions of organisms and their environment
ecosystems
interdependent collections of living things
environment
the nonliving chemical and physical parts of an ecosystem, including the water, soil, and atmosphere
ecological niche
the habitat, functional role, requirements for environmental resources, and tolerance ranges within an ecosystem
fungi
one of the five Linnaean kingdoms, organisms that obtain energy by absorbing materials through filaments and reproduce by production of spores. may be single- or multi-celled
fermentation
an anaerobic cellular process in which pyruvic acids are broken down and the energy is used by the cell to keep glycolysis going
glacier
a large body of ice that slowly flows down a slope or valley under the influence of gravity; found primarily in Greenland and Antarctica
ground water
fresh water from the surface, which typically percolates into the ground and fills the tiny spaces between grains of sandstone and other porous rock layers
glycolysis
the first step in the extraction of energy from glucose, which takes place in ten separate steps, each of which is governed by a specific enzyme, and which splits each glucose molecule into two smaller molecules called pyruvic acid
gymnosperms
the class of vascular plants that produce seeds without flowers such as fir trees
greenhouse effect
a global temperature increase caused by the fact that Earth’s atmospheric gases trap some of the sun’s infrared (heat) energy before it radiates out into space
greenhouse effect
a global temperature increase caused by the fact that Earth’s atmospheric gases trap some of the sun’s infrared (heat) energy before it radiates out into space
hydrologic cycle
the combination of processes by which water moves from repository to repository on Earth’s surface
homo sapiens
the single species which includes all branches of the human race; recognized in fossils as old as 200,000 years
ice caps
layers of ice that form at the north and south polar regions of Earth
ice age
a period of several million years during which glaciers have repeatedly advanced and retreated, causing radical changes in climate and influencing human evolution
invertebrates
organisms without backbones
igneous rock
the first rock to form on a cooling planet, solidified from hot, molten material; intrusive or extrusive
intrusive rock
igneous rock that cools and hardens underground
jet stream
a high-altitude stream of fast-moving winds that marks the boundary between the northern polar cold air mass and the warmer air of the temperate zone
kingdom
the broadest classification in the Linnaean classification system, corresponding to the coarsest division of living things
Linnaean classification
a systematic attempt by Swedish naturalist, Carolus Linnaean to catalogue the diversity of all living things according to their shared characteristics so that each organism is as close as possible to those things it resembles, and as far apart as possible from those it does not
law of unintended consequences
a phenomenon demonstrating the interdependent nature of ecosystems; it is virtually impossible to change one aspect of an ecosystem without affecting something, often inadvertently
mammals
one of a group of vertebrates made up of individuals that are warm-blooded, have hair, and whose females nurse their young. human beings are mammals
metamorphic rock
igneous or sedimentary rock that is buried and transformed by Earth’s intense internal temperature and pressure
mitosis
the process of cell division producing daughter cells with exactly the same number of chromosomes as in the mother cell
meiosis
the division process that produces cells with one-half the number of chromosomes in each somatic cell. each resulting daughter cell has half the normal complement of DNA
mitochondria
sausage-shaped organelles that are places where molecules derived from glucose react with oxygen wo produce the cell’s energy
metabolism
the process by which a cell derives energy from its surroundings
nucleus
prominent structure in interior of the cell that contains its DNA and controls the cell’s chemistry
ozone layer
a region of enhanced ozone 20-30 miles above Earth’s surface where most of the absorption of the sun’s ultra-violet radiation occurs
ozone hole
a volume of atmosphere above Antarctica during Sept through Nov in which the concentration of the trace gas ozone has declined significantly
organelle
any specialized structure in the cell, including the nucleus
plants
multicelled organisms that get their energy directly from the sun through photosynthesis. one of 5 kingdoms according to Linnaean classification
primates
an order of mammals that have grasping fingers and toes, eyes at the front of their heads, large brains, and fingernails instead of claws; includes monkeys, apes, and humans
photosynthesis
the mechanism by which plants convert the energy of sunlight into energy stored in carbohydrates, the chemical energy of virtually all life on Earth
reservoirs
locations where a substance is to be found. Earth’s water, for ex, is found in oceans, rivers, ice caps, and several other reservoirs
rock cycle
an ongoing cycle of internal and external Earth processes by which rock is created, destroyed, and altered
receptor
a large structure found in the cell membrane and made of proteins folded into a geometrical shape that will bond chemically only to a specific type of molecule
respiration
the process by which animals retrieve energy stored in glucose, in a complex series of cellular chemical reactions, which include breathing in oxygen produced by plants, burning carbohydrates for food, and breathing out carbon dioxide
species
the basic unit of Linnaean classification; and interbreeding population of individual organisms
sedimentary rock
a type of rock that is formed from layers of sediment produced by the weathering of other rock or by chemical precipitation
vertebrates
a subphylum of chordates in which the nerves along the back are encased in bone
vascular plants
the phylum of plants that have internal “plumbing” capable of carrying fluids from one part of the plant to another
taxonomy
the science of cataloguing living things, describing them, and giving them names
weather
daily changes in rainfall, temperature, amount of sunshine, and other variables resulting partly from the general circulation in the atmosphere, and partly from local disturbances and variations
volcanic/extrusive rock
extrusive igneous rock that solidifies on Earth’s surface
