Usually, some energy is &quot;lost&quot; or transferred into friction (heat and movement loss), so efficiency is never 100%. Still the overall amount of energy remains the same.
All because of the atoms that form them - different atoms have different properties that react depending on their number of protons, electrons & neutrons
Review 5 states of matter: solid, liquid, gas, plasma, BE condensate Explore ptable.com to see state changes at different temperatures
The letter “H” stands for hydrogen while the letter “O” stands for oxygen. The subscript of “2” after the “H” tells us that there are 2 hydrogen atoms in a water molecule. The fact that there is no subscript after the “O” tells us that there is one oxygen atom in a water molecule. Thus, the chemical symbol “H 2 O” means “two hydrogen atoms and one oxygen atom.” Chemical symbols like this are called chemical formulas , because they provide a formula by which you can understand the chemical makeup of any substance. For example, natural gas stoves, water heaters, and furnaces burn a gas called methane, whose chemical formula is CH 4 . As we already know, the chemical symbol for hydrogen is “H. The chemical symbol for carbon is “C.” Thus, this chemical formula tells us that a molecule of methane contains one carbon atom (there is no subscript after the carbon&apos;s symbol) and four hydrogen atoms (there is a subscript of “4” after hydrogen&apos;s symbol). These atoms, when linked together in those numbers, make a molecule of methane. Notice what I needed to know to interpret a chemical formula. First, I needed to know the chemical symbols for each atom. Second, I needed to realize that if there is no subscript after a chemical symbol, that means there is only one of those atoms in the molecule. If there is a subscript, then the subscript tells me how many of those atoms exists in the molecule. So, in order to really be able to use chemical formulas, we will need to memorize all of the symbols for all of the atoms out there, right? Of course not. In this course, I will tell you the chemical symbol for any atom that you need to know. Eventually, you will become used to associating the most popular atoms with their symbols. You need to remember, however, that not all atomic symbols are composed of just one letter. Some atoms have two letters in their symbol. The chemical symbol for neon, an atom that comprises the gas used in neon signs, is “Ne.” Notice that even though there are two letters in this symbol, only one of them is capitalized. That is a general rule. All atomic symbols have only one capital letter. If there is a second letter in the symbol, it is always the lower case version of that letter. Also, you must realize that chemical symbols are not always as easily recognized as “C” for carbon and “Ne” for neon. The symbol for an iron atom, for example, is “Fe.” Where does that come from? Well, the Latin name for iron begins with the letters “f” and “e.” So sometimes we use two letters in an atomic symbol and sometimes we use one. Also, sometimes we base the symbol for an atom on its English name and sometimes we base it on its Latin name. Given all of that, make sure you understand the concept of chemical formulas by solving the “on your own” problems that follow.
What comes to mind when you think of &quot;poles&quot; (geographic N/S pole, battery terminals). Ionic bonds = electrons stripped/stolen/donated to form ions (remember NaCl?). Covalent bonds = shared electrons. In the case of water, there is actually a tug-of-war going on between the electrons that are supposedly being “shared” by the atoms. Much like two little children who continually fight over a toy that they are supposedly “sharing,” the oxygen atom and each hydrogen atom fight over the electrons that they are supposedly sharing. Continuing our analogy, suppose one of the children is stronger than the other. In the absence of proper adult supervision, the stronger child will end up with the toy more often than the weaker child, right? Well, it turns out that oxygen is stronger at pulling on electrons than is hydrogen so the oxygen atom will end up with the electrons more often than will the hydrogen. What&apos;s the big deal? Sure, oxygen isn&apos;t “playing fair,” but why worry about it? Remember that electrons are negatively charged. Since the oxygen gets the electrons more often than the hydrogens, it possesses more than its “fair share” of electrons. Since it possesses more than its “fair share” of electrons, it develops a very slight negative electrical charge. In the same way, since the hydrogen atoms get less than their “fair share” of electrons, they have less negative charge than they should. With less negative charge than they should have, they end up having a slight positive charge. The symbol δ is the lower-case Greek letter delta, and it is used to signify the fact that the electrical charges in the water molecule are very small. When you have positive and negative charges within the same structure, the phenomenon is called polarity (pol&apos; air uh tee). As a result, we call water a polar molecule . Polar molecule - A molecule that has slight positive and negative charges due to an imbalance in the way electrons are shared
Notice what hydrogen bonds do. They link molecules together. Chemical bonds link atoms together to form molecules. Hydrogen bonds, on the other hand, bring individual molecules close together, linking them. Thus, while a chemical bond forms between atoms, a hydrogen bond forms between molecules. Also, since hydrogen bonds are weak, they can be easily broken. For example, if you boil water, you are adding enough energy to the water to pull the water molecules far apart, breaking the hydrogen bonds. Despite the fact that the hydrogen bonds break, the chemical bonds which hold the two hydrogen atoms to the oxygen atom do not break. Water vapor is still H2O, so the chemical bonds still hold. The molecules are so far apart, however, that the hydrogen bonds are eliminated.
At sea level, pure water boils at 100°C & freezes at 0°C Water&apos;s polarity forces molecules, as they slow down, to arrange themselves in a fixed crystal lattice formation. This formation causes ice to be less dense than liquid water. In its liquid form, water molecules are constantly moving around, sliding past each other and frequently forming and breaking hydrogen bonds. Because of this molecular movement, the molecules overall are closer together than in its solid state. Why is this important?
How do plants and trees hundreds of feet tall transport water up from the roots to the leaves without a pumping circulatory system? How do water bugs (or a paper clip) &quot;float&quot; on the top of ponds? Polarity of water results in cohesion (stickiness of molecules) that also creates surface tension Force of gravity on paper clip (or water bug) is less than the cohesive force of water (molecules clinging to each other at the surface more than they do in the solution because they are attracted to each other much more than they are attracted to the air).
Water has a very high specific heat - lots of energy to raise or lower the temperature of water. stickiness makes water molecules cling together & resistant to vaporizing slipperiness makes water molecules repellant and keep sliding past each other (resistant to freezing) Water can absorb or release relatively large amounts of heat with only a slight change in its own temperature. Water stabilizes air temperatures by absorbing heat from warmer air and releasing heat to cooler air.
Perhaps the largest aquifer in the world is the Ogallala aquifer located in the Midwestern part of the United States. This aquifer is named after a Sioux Indian tribe. It is estimated to be more than two million years old and to hold about 650 trillion gallons (2,500 trillion liters)! It underlies parts of 8 states, stretching about 800 miles (1,288 km) from South Dakota to Texas. The Ogallala aquifer supplies vast amounts of water to irrigate the crops grown in this vitally important agricultural area.
When scientists speak of “salt,” they are actually talking about a large class of substances, of which sodium chloride is a member. There are many other substances that fall within the classification of “salt,” however. Have you ever heard of someone soaking their feet in a mixture of Epsom salt and water? Epsom salt is another member of the “salt” class; its specific name is magnesium sulfate. To a scientist, then, many of the substances I lumped into the “other” category are considered “salts” as well. Thus, you might hear someone say that ocean water is about 96.5% water and about 3.5% salt. That&apos;s true, but the person saying that is obviously using the term “salt” to mean a class of substances, not just table salt.
After a while, the whole mass of ice and snow gets so heavy that it starts to slowly slide down the mountain. The speed at which glaciers slide is rather slow, usually about 1 meter (a little more than 3 feet) per day. Glaciers have been recorded moving more rapidly, however. In 1937, the Black Rapids Glacier in Alaska was observed moving more than 30 meters (more than 100 feet) per day. As a glacier moves, it tends to sculpt the earth over which it is traveling, plowing earth and rocks out of the way, often making valleys where there were none before. As the glacier travels down the mountain, it will often reach an altitude where the snow and ice begin to melt faster than new snowfall can replenish it. At that point, the glacier starts to melt, feeding many freshwater sources in the hydrosphere. Glaciers in the polar regions of the earth, however, never reach that point, and they continue to flow into the sea, forming huge sheets of ice (ice shelves that extend over the ocean). The continent of Greenland, for example, is almost entirely covered in a huge sheet of ice that comes from two glaciers! The entire Antarctic continent is covered by a glacier which occupies an area of more than 13 million square kilometers (5 million square miles)! photos: top - piedmont glacier (room to spread out creates a wide &quot;bowl&quot;) bottom - satellite photo of Greenland&apos;s continental ice sheet
Glaciers move by internal deformation and/or by sliding at the base. Internal deformation occurs when the weight and mass of a glacier causes it to spread out due to gravity. Sliding occurs when the glacier slides on a thin layer of water at the bottom of the glacier. This water may come from glacial melting due to the pressure of the overlying ice, or from water that has worked its way through cracks in the glacier. Glaciers can also readily slide on a soft sediment bed that has some water in it. When a glacier moves rapidly, internal stresses build up in the ice which cannot be relieved by deformation alone, and cracks (called crevasses) form at the surface of the glacier. Glaciers erode the rock underneath them. A glacier can &quot;carve&quot; a valley, wearing away rocks and soil through abrasion and plucking up and moving large pieces of rock and debris. The glacier pushes this earth and rock forward as it advances, almost like a conveyor belt, and dumps it to the side along the way or at the end of the glacier (deposition). Depositional features include moraines, drumlins, and eskers.
At some point, such glaciers move so far out into the sea that they end up in water deeper than they are thick. At that point, since ice floats in water, the glacier begins to float. Typically, large chunks of the end of the glacier break away, forming icebergs . As you probably know, the vast majority (about 90%) of an iceberg exists below the surface of the water, so what we can see of an iceberg is really only about 10% of the total. This is easy to understand if you look at an ice cube floating in a glass of water. We know that ice floats in water, but not very well. Since the mass of ice is only slightly smaller than the mass of an equal volume of water, only a small portion of the ice cube can actually float above the surface of the water. The same is true for an iceberg. This is what makes them dangerous to ships. As a ship travels, it might see the tip of an iceberg and steer clear of it. However, since 90% of the iceberg is under water, it is very possible that even though the ship steers clear of the portion of the iceberg that can be seen, the bottom of the boat can still collide with the other 90% of the iceberg that is under water! Sometimes the glaciers do not break apart as they float, and they end up forming vast ice shelves that extend out into the ocean. One such ice shelf is called the Ross Ice Shelf , and it covers a portion of the Antarctic ocean that is about the size of Texas. In the end, then, an iceberg is really a portion of a glacier that has broken off and floats in the ocean. Ice shelves are simply the ends of glaciers that float in the ocean. A glacier is the result of heavy snowfall in the mountains that does not melt away during the summer. So the largest sources of freshwater on the planet (icebergs and glaciers) are really the result of precipitation. After all, without snowfall in the mountains, none of this would ever happen!
RELATIVE HUMIDITY: The relative humidity tells how much water the air is holding compared to how much it could hold at a certain temperature. Lets imagine we have a blob of air with moisture in it. The temperature of our blob of air is 80 degrees. So, how do we tell how much moisture is in it ???? If our blob of air has a relative humidity of 50% then that means it is holding half of the amount of water a blob of air 80 degrees could hold. The relative humidity can change if the moisture changes or if the temperature changes. At 37 degrees C, air is capable of holding onto 44 mg of water vapor in each liter - so an absolute humidity reading of 22 would be 50% relative humidity.
Although not considered forms of precipitation, dew and frost are two other means by which water can leave the atmosphere and make it back to the earth. Dew forms when air near the surface of the earth gets cool. As this happens, the water vapor in the air will tend to condense into liquid. The problem, however, is that water vapor will not condense unless it can do so onto something. That&apos;s why clouds need cloud condensation nuclei in order to form. Near the surface of the earth, water will condense onto plants and soil, forming water droplets. These water droplets are called dew. The temperature at which dew forms, called the dew point, depends on the pressure and humidity of the air. The higher the pressure and humidity, the higher the dew point.
During autumn or winter, the air near the surface of the earth may get colder than the freezing point of water. When this happens, water vapor skips the liquid stage and immediately freezes on any surface with which it can come into contact, covering the surface with frost. Like dew, however, frost can only form on a surface. The temperature at which this occurs is called the frost point. The low temperatures which cause frost can be deadly for certain plants, so gardeners often cover their plants during cold nights to try and keep the cold air away from them.
Unit 2 Review
Water's Special Properties & The Water Cycle
In your lab notebook, please answer as best you can:
1. Where do glaciers form?
• High elevations & latitudes (polar regions) where more snow falls than
melts each year.
1. Where do icebergs come from?
• Glaciers (chunks of ice break off into the sea from tidewater glaciers)
3. True or False: glacial ice moves out in all directions from the center of
greatest accumulation of a confined glacier.
• False– confined glaciers move downhill in one direction
4. Chunks of ice breaking off into the sea from tidewater glaciers is called:
4. What does “permeable” mean?
• Contains pores (tiny pockets or spaces) that water can run through.
Bonus Question: How is sea ice different than icebergs?
-Sea ice = thin sheets from frozen ocean water
-Icebergs = big chunks of glacier ice
The Wat er Cycl e & Gl aci ers
1. The amount of Earth’s FRESH water which can be found flowing in lakes,
streams, rivers, and wetlands. 0.3%
2. Percentage of Earth’s FRESH water stored underground in aquifers and in
the soil? 30.1%
3. Earth’s fresh water trapped in glaciers & sea ice? 68.7%
4. A region surrounded by higher ground from which precipitation drains into
a river system: watershed
5. An aquifer is an underground layer of permeable rock, sediment, or soil
that contains water.
6. The top of the saturated zone of underground water levels in an area is
referred to as the water table
7. What happens when soil becomes fully saturated with precipitation?
Puddles, ponding, and flooding can occur
Wat er Cycl e & Gl aci ers worksheet
8. What affect do homes and farms using well water (pumped from aquifers)
have on the water table if they pull water out faster than precipitation can fill
it back up?
The water table is lowered in that area.
9. WHY will precipitation percolate down into an aquifer more quickly if the
surface layer is rocky rather than composed of fine clay particles?
Larger rock and soil particles have more spaces between them for water to
fill and flow through.
10. Describe how a snowflake becomes part of a glacier.
After about a year, a snowflake that gets buried and pressed down below
layers of snow above becomes firn (rounded ice globs). With more
pressure, all the air is pushed out an solid glacier ice is formed.
Wat er Cycl e & Gl aci ers worksheet
11. Explain the difference between these types of glaciers:
Confined: form at high elevations on the sides of mountains and flow
Unconfined: form in polar regions, cover entire mountain ranges, islands, or
continents, & flow out from the center
12. Alpine glaciers move in part due to basal sliding as the heavy ice is pulled
by gravity downhill.
13. Three factors affect the speed of glacial movement:
Thickness of the ice
Temperature of the ice.
Steepness of the glacial slope
14. What direction does the ice flow in polar ice caps and ice sheets?
- ice flows out in all directions from the point of greatest accumulation
15. Give a short definition for each of the following:
Piedmont glacier: spreads out at the bottom of a valley
Tidewater glacier: a glacier that runs down into the ocean
Wat er Cycl e & Gl aci ers worksheet
Tidewater glacier: a glacier that meets the ocean
Cirque: bowl-shaped depression left by an alpine glacier
Moraine: line of debris (deposited rock & soil) left by glacier
Crevasse: deep cracks in a glacier
Glacial flour: fine-ground rocks (silt) made by glacial erosion-
Tarn: small mountain lake left behind by a glacier
16. The process of solid matter (such as ice) changing directly into a gas (water
vapor) is called: sublimation
17. Explain how glaciers erode Earth’s surface:
Glacial quarrying (plucking): rocks are frozen into the glacier & then carried
Abrasion: rock debris frozen into the glacier scrapes & grinds away the bedrock
18. What two factors determine whether a glacier grows bigger or retreat?
Precipitation & temperature
19. Explain where the water frozen in icebergs comes from.
Snowfall is compacted into glaciers, which break off into the ocean to form
Wat er Cycl e & Gl aci ers worksheet
Precipitation Transport Condensation
• NATURAL RESOURCE:
– Anything naturally occurring on our planet that is
necessary or useful to humans
• Renewable Resource:
Resources that can be
replenished by natural processes
at least as quickly as they are
• Fresh Water, Hydroelectric energy
• Clean Air, Wind energy
• Land (for agriculture)
• Plants & Animals (Biomass Fuels)
• Geothermal energy
• Nonrenewable Resource:
Resources being used up
faster than they can be
replaced by natural processes.
• Fossil Fuels
• Coal, oil, natural gas
• Metals, gems, & nonmetals
• Land (for building/mining)
• Radioactive Elements
Law of Conservation of Energy
• Energy cannot be created or destroyed
Law of Thermodynamics)
– it can only be converted from one form to another
– the total energy in a system must remain constant
• Formed when plant material is heated &
compressed underground for many years.
• Chemical energy in plant molecules is
concentrated into a combustible fuel.
– mined out of the ground
– Forms from woody plant material
• Natural gas
– flammable methane gas
– found near petroleum, underground
• Oil (petroleum)
– liquid found underground between
folds of rock
– Forms from slimy plant material
– burned for electricity, heat, and in
• Natural gas
– used to heat homes, generate
electricity, & for manufacturing
– Gasoline & Diesel fuel
• for transportation (cars, trucks,
airplanes, ships, trains)
• petroleum jelly, grease, engine oil
• paved roads, parking lots, etc.
– Kerosene, propane, butane
• burned for light/heat
Atoms of the same kind combine to form a pure elementelement
i.e. gold (Au), oxygen (O), sodium (Na), or argon (Ar)i.e. gold (Au), oxygen (O), sodium (Na), or argon (Ar)
Two or more atoms joined together is called a molecule
i.e. water (H2O), ozone (O3), or carbon dioxide (CO2)
Two or more types of atoms joined together = a compoundcompound
Of the molecules listed above, water and CO2 are compounds
Ozone is not a compound
because it is made of only oxygen
Interactive Periodic Table
• Smallest possible unit into
which matter can be
divided, while still
maintaining its properties.
• Made up of:
For example, you can take a book and divide it into chapters, paragraphs, sentences
and words. You could even chop up the words into letters, but they wouldn’t work
together to make sense any more, and you certainly wouldn’t have a book anymore.
Atoms are like words, made up of smaller parts (letters), but not sensibly
divisible. Atoms join together to form molecules (sentences). Even
different molecules can be combined to form unique mixtures
Changes of State
• What affects a substance’s physical state?
• Adding heat (energy) excites the atoms/molecules, causing them to
move faster and more randomly (entropy)
• Adding pressure “immobilizes” or constrains the atoms/molecules
– i.e. Earth’s inner core is solid even though temperatures are high
• Gases are the only state of matter than can be compressed (made
denser with pressure)
• Bonding between
• i.e. Water’s
H-bonding gives it
a high boiling point
The Carbon Cycle
• CO2, H2O, C6H12O6
• Show how many and which
type of atoms make a
• How many atoms form one
• 3: 1 oxygen and 2
• Oxygen hogs the electrons
• Hydrogen atoms don't get
their fair share of "shared
• Water is a polar molecule
– Oxygen end of molecule =
slight negative charge
– H end = slightly positive
• NOT an ion (no net charge)
• Attraction between oppositely charged
regions of water molecules
• Each molecule can have H-bonds with
four other water molecules
• Weak bonds continually break & reform
Frozen Water's Density
• Water freezes at 0° C (32o
• H2O is most dense at 4° C (as a liquid)
– In most other substances, the solid phase is most dense
• Crystal lattice formation the result of water's polarity
• Density of solid H2O is 9% less than liquid H2O
Cohesion & Adhesion
• Cohesion: attraction between particles of the
same substance (i.e. water molecules)
– Results in Surface Tension
• molecules at the surface cling together
• Adhesion: Attraction between particles of
different substances (i.e. water and glass)
– Explains capillary action
• water molecules “tow” each
other along in a thin tube
Water Resists Temperature Changes
• Heat = how fast molecules are moving
• Water's polarity makes the molecules both "sticky" and
"slippery" (like magnets that attract & repel)
– stickiness: resistant to vaporizing because of cohesion
– slipperiness: resistant to freezing because they keep sliding around
• Specific Heat = energy needed to raise or lower 1g of anything
by 1° C
– Water has a very high specific heat
• Water stabilizes air
– Absorbs/releases large
amounts of heat with only
a slight change in its own
• Water boils at 100°C (212o
– LOTS of energy to break hydrogen bonds
• Evaporation can occur at much lower temperatures, when
molecules at the surface of a liquid change to their gas state
• Water vapor in atmosphere resists temperature changes
• Evaporation absorbs lots of heat energy
– Evaporative cooling (sweat, panting, seashore)
• Precipitation seeps down through soil & rock
• Layers act as filters that trap contaminants
• Water table: imaginary line between the water-logged
soil and the soil not saturated with water
– varies with seasonal precipitation, pumping, & geography
• Two types of aquifers:
– unconfined: water supply
which has a solid layer of
rock under it, but a
permeable layer of rocks
– confined: water supply
sandwiched between two
solid rock layers through
which water cannot pass
• pressure builds up and can
form an artesian well
Earth's Water Distribution
• 97% in oceans (salt water)
• 2% trapped in glaciers, icebergs and polar ice caps
• .7% groundwater and soil moisture
• .01 % surface fresh water (lakes, rivers, wetlands)
• .001% atmospheric moisture
(rain, dew, water vapor)
– Confined valley glaciers
move down mountainsides
– Unconfined polar ice caps &
ice sheets flow outward in
all directions from a central
– Typically move 1 - 3 meters
each day but can have
“surges” of faster
• Years of continual snows
compress layers below
– Firn (hard-packed ice)
– Polar or high-elevation areas
• Thick layers get heavy/dense
• Insulated bottom layer melts
& gravity pulls downhill
• Plucking: rocks are picked up & carried
• Abrasion: frozen debris grinds away
bedrock below as glacier flows down
• Rocks & soil are deposited into lines of debris called moraines
• Crevasses form when glaciers move quickly (up to 30 m/day)
• Retreat: melting occurs faster than snow accumulates
• Tidewater glaciers reach the ocean or
• Calving occurs as big chunks of the glacier
fall off into the ocean to become icebergs
– Ice Shelf = portion of connected glacier
floating on water (may be miles wide/long)
– 90% of iceberg remains below water surface
• Absolute humidity: tells the amount of moisture in the air
– warm air holds more water vapor than cool air
– example: absolute humidity of 8.7 mg/m3
• Relative humidity - tells
how much water the air
is holding compared to
its saturation point (the
most it could hold) at a
– 50% humidity means the
air is holding half of the
moisture it is able to hold
at that temperature
• Ground-level condensation
– vapor condenses into liquid droplets as it
touches cooler ground surfaces
• Dew Point = temp. at which atmospheric
– varies depending on the humidity (how much
vapor is in the air)
• Frozen dew
– water vapor skips liquid form and freezes
as it touches below 0o
C ground surfaces