topic 1 >-< Flashcards
ocean water
Know the freezing point of freshwater and saltwater
- freshwater: 0C / 32 F
- saltwater: -2C / 28.4F
Be able to explain the change in molecular speed with increased temperature
As temperature increases molecular speed increases according to the kinetic particle theory
Be able to explain what the hydrogen bonds look like when ice forms
lattice structure/ crystalline structure
Be able to define the kinetic particle theory
describes all matter as a collection of particles that are in constant, random motion (even if the movements are only small vibrations)
Understand how the spacing and movement of molecules changes with state (SOLID)
Solid: arranged in a lattice structure fixed in position (ice)
When ice is heated water molecule are given more energy, resulting in them vibrating faster until the forces holding the molecules together start to break. (Breaking of hydrogen bonds)
The water molecules nearest the outer surfaces of the ice crystals break free and flow away taking shape of the container they are in.
Understand how the spacing and movement of molecules changes with state (LIQUID)
Liquid: water molecules are closely packed to each other in a liquid but are able to move freely past each other (cannot be compressed and take shape of the contained they are in)
When liquid water is heated, the particles gain more energy, making them move faster and slightly further from each other.
Understand how the spacing and movement of molecules changes with state (GAS)
Gas: Water vapour (vapor) term given to the gaseous water (both from evaporation and boiling)
Boiling is 100 degrees Celsius at 1 atmospheric Pressure
Be able to identify a covalent bond
Covalent bond: two atoms share a pair of electrons (Covalent bonding occurs in most non-metal elements and in compounds formed between nonmetals)
Be able to identify a hydrogen bond
Hydrogen bonding is a special type of dipole-dipole attraction between molecules, not a covalent bond to a hydrogen atom.
It results from the attractive force between a hydrogen atom covalently bonded to a very electronegative atom such as a N, O, or F atom and another very electronegative atom.
Know what the atomic number of an element is, and be able to determine the number of electrons from it
atomic number: the number of protons contained in the nucleus of an atom
Electron: a negatively charged subatomic particle that orbits the nucleus of an atom
An atom has an equal number of protons as electrons, so they are neutral, but….
An ION is an atom or a molecule that has lost or gained one or more electrons creating an electrical charge. (Cations- lost electrons, Anions- gained electrons)
Be able to determine how many shells an atom has based on its electron count
1st Shell: nearest to nucleus can hold 2 electrons (only shell present in hydrogen and helium)
2nd Shell: holds up to 8 electrons
3rd Shell: holds up to 18 electrons
4th Shell: holds up to 32 electrons
Know the definition of the term polar molecule
A polar molecule is a molecule in which one end of the molecule is slightly positive, while the other end is slightly negative. Examples: H2O, HF, NH3, SO2
Know the difference between Halocline, thermocline, and Pycnocline. (Significant Changes in abiotic factors happen at these locations)
Thermocline: a layer between two layers of water with different temperatures
Halocline: a layer of water below the mixed surface layer where a rapid change in salinity can be measured as depth increases
The Surface layer (0-200m) is the best-mixed area of the ocean. (Turbulence is created from wind and currents so this layer is typically uniform across the ocean. Mixing of layers are typically density driven. For example, if the surface of the ocean cools, density of water will increase and the water will sink carrying all the nutrients and gaseous contained in that surface layer.
Pycnocline: a layer of water between two layers of water with different densities
Pressure increases with depth compressing the water molecules together, forcing more molecules into smaller volumes. Also as salinity increases, density also increases. This indicates that the saltiest water is at the seabed. However, there is one exception, the tropical seas (between 30 N and 30 S latitudes) high evaporation rates equals high salinity.
Tropical region (temperature)
decreases w/ depth
Surface layer could be 25 degrees celsius or more but experiences a drastic decline with depth.
tropical region (salinity)
decreases w/ depth
High evaporation = high salinity at surface, followed by a steep decrease, followed by a slow increase
If it rains a lot, salinity may increase w/ depth slightly after the surface layer
tropical region (density)
increases w/ depth
Defined pycnocline: surface water density is a lot less dense than the lower layers
polar region (temperature)
decrease w/ depth (less dramatic)
Surface is close to freezing and remains constant with increasing depth.
No mixed layer or pycnocline exists in the highest latitudes since sm heat is lost to the cold atmosphere that the temp cools very quickly to a similar temp to the bottom water
, i.e. no temp gradient.
polar region (salinity)
increases w/ depth
Lower salinities at the surface and increases as you go deeper.
Cold and fresh water in the surface mixed layer is separated from a layer of warm saline Atlantic water by a cold and stable layer, the cold halocline.
polar region (density)
Nonexistent
no thermocline = no pycnocline.
In the high latitudes the water is uniformly cold at all depths, so there is little density stratification. The lack of a pycnocline (or a thermocline) allows cold, nutrient-rich deep water to mix with the surface water more easily, leading to higher primary production in polar regions.
Be able to describe why a thermocline may be pushed deeper in the winter.
During the summer, the mixed layer is shallow, often only about 10-20 meters deep, but during the winter, cooler atmospheric temperatures and stronger winds can cause the mixed layer to expand to more than 100 meters.
Know the effect of temperature on density
temperatureincreases, density decreases.
Be able to state the density of freshwater, saltwater, and ice
Freshwater: 1.00 g/ml
Seawater: 1.03 g/ml
Ice: .917 g/ml
Be able to calculate the mass or volume of freshwater when given the other value
Density = mass/volume
Understand that ice floats on water due to density differences and the effect this has on polar marine ecosystems
The underside of icebergs and ice sheets function as a habitat for species of phytoplankton and algae that can grow there.
The growth of these producers helps support the Arctic and Antarctic ecosystems throughout the winter months when the food supply should be too low to maintain the food web.
Be able to provide an example of an animal dependent on the ice for survival
Floating ice sheets provide a habitat for animals such as penguins (southern hemisphere/ antarctica) and Polar Bears (Arctic Ocean) to hunt from.
Know the effect that floating ice has on the temperature of the water below it
When ice forms on a body of water, it begins to act as a thermal insulator, reducing the rate of further heat loss from the water beneath it.
The water under the ice is warmer than the water exposed to the freezing air above the ice, allowing marine organisms to stay at a temperature that is better suited for their adaptations.
Solute
solid that dissolves in a solvent
Solution
a mixture of a solute dissolved in a solvent
Solubility
the ability of a solute to dissolve within a solvent (such as water).
Be able to identify the two most common salt ions dissolved in water.
Chloride and Sodium Ions
Know which type of bond holds a NaCl molecule together
ionic bond
Know the definition of salinity
a measure of the quantity of dissolved solids in ocean water, represented by parts per thousand (ppt) or 0/00
Understand why water is the “universal solvent”
The polarity of water allows it to form bonds with an unusual number of substances, making water one of the best solvents on the planet.
Be able to explain why increasing salinity lowers the freezing points of water
This concept is called “freezing point depression.” Essentially, the salt makes it harder for the water molecules to bond together in their rigid structure.
Be able to explain how run-off impacts the salinity of seawater
the flow of water from the land caused by precipitation. (freshwater runoff will lower salinity, but runoff with nutrients, pesticides, fertilizers, and oils might have a different effect.)
Be able to explain how precipitation impacts the salinity of seawater
water that falls from the atmosphere to the Earth’s surface as rain, sleet, snow or hail. (lowers salinity)
Be able to explain how evaporation impacts the salinity of seawater
Change of state from liquid to gas below the boiling point of a substance (increases salinity)
Know the three techniques used to measure pH
Litmus indicator: only determines if a substance is an acid or an alkali, it cannot show how strong or weak it is.)
Universal indicator: shows a range of strengths for acids and alkalis: scientist then compare the color of the paper to the color pH scale provided to give a whole number pH. (subjective)
pH probes: measure hydrogen-ion concentration within a solution to provide a numerical read-out that is more precise and less subjective than other methods.
Know the pH of distilled, pure water
7 neutral
Know the approximate average pH of the oceans
8.1 (slightly alkaline)
Understand how the ratio of H+ and OH- differs along the pH scale
Acids: pH is below 7 (high concentration of Hydrogen Ions)
Bases (Alkaline): pH is above 7 (low concentration of Hydrogen Ions, more Hydroxide Ions)
Be able to explain the sources of oxygen and carbon dioxide to the ocean
Gases in the atmosphere are in a state of equilibrium with the gases dissolved in ocean water.
As the concentration of a particular gases raises in the atmosphere the concentration of the gas in the seawater will also increase.
Mixing as a result of turbulence and wave action works to maintain equilibrium.
The more turbulent it is the easier it is for gases in the atmosphere to dissolve in the ocean.
This leads to higher concentrations of CO2 and O2 in the upper 200m of the ocean.
Know which of the two (carbon dioxide & oxygen) is most soluble in water and why
Carbon dioxide is very soluble in seawater because of its ability to form carbonic acid (a weak acid).
Oxygen has a low solubility because it does not chemically combine with the water molecules.
This means the level of carbon dioxide held by seawater is higher than that of oxygen.
be able to explain the effect that an increase in an acid will have on the overall pH of the seawater
Historically the pH of the open ocean has been an average of 8.2.
however, because of carbonic acid the worldwide average dropped to 8.1.
In a linear scale 0.1 decrease in pH would indicate a 1% increase in acidity, but the scale is logarithmic, a 0.1 decrease in pH is actually a 25% rise in acidity.
Be able to describe the oxygen minimum layer and list the biological processes that are and are not occurring there that are impacting the oxygen concentration (photosynthesis, respiration, and decomposition)
the layer within the ocean where the concentration of dissolved oxygen is at its lowest
lack of oxygen being introduced into the water and consumers still performing respiration to survive.
Know approximately at what depth the oxygen minimum layer occurs
between 100m and 1000m deep. (typically at a depth of 500m)
Be able to explain whether cold or warm water holds more gases and why
Cold water can dissolve more gas than warmer temperatures.
When water increases in temperature its molecules move faster.
