EPS SCI 15 Lecture 5 Review

Atoms consist of:

Protons + neutrons, = nucleus + electrons

Protons are ______ charged?

Positively

Electrons are ________ charged?

Negatively

Molecules can be __________ or _________, they can have _______, ________, or _______ bonds

diatomic or polyatomic, single, double, or triple

Diatomic:

A molecule that consists of exactly 2 atoms

Polyatomic:

Containing more than 2 atoms

What do atoms do in covalent bonds?

2 atoms share electrons

If one atom pulls the electron closer to its center, it:

Gains a slightly more negative charge

What happens when the charges in a molecule are located at 2 ends?

A dipole forms

What do valent electrons do in ionic bonds?

The valent electrons move from one atom to another

The valent atom that gives electrons becomes

Positively charged (cation)

The valent electron that receives electrons becomes

Negatively charged (anion)

What is the amount of heat needed to raise the system’s temperature by one degree (C or K)?

Heat capacity

What fluid has a very high heat capacity (it takes a lot of energy to heait it up compared to other systems)?

Water

How do oceans play an importaant role in regulating our climate?

They have a high heat capacity (takes a lot of energy to heat compared to other systems), places close to the ocean have much milder (less extreme) annual temperatures

Water can form 3 physical states of matter found on Earth:

Solid, liquid, gas

Water, at atmospheric pressure and sea level, freezes/melts at _____ and boils/condenses at ______

0 degrees C, 100 degrees C

The density of liquid water changes:

Non-linear with temperature

What degree C does water (freshwater) reach its highest density?

4 degrees C

Ice has a _______ of liquid water

Lower density

What do the anomalies in water/ice density prevent?

During winter/ in cold regions, anomalies prevent lakes and oceans freezing all the way to the bottom

What is a way to transport heat through the movement of liquids?

Thermal convection

When heated, water __________ and rises, and vice versa, water (>4 degrees C) __________ when cooled and sinks.

Loses density, increases its density

Why do water molecules form hydrogen bonds? What makes water an excellent solvent for all charged substances (like the ions of salts) but not for non-polar substances like oil?

Polarity

pH describes:

Concentration of H+ and OH- ions in water

What is pH an expression for?

How acidic or alkaline a solution is

At neutral pH 7, H+ and OH- are __________

Balanced

At pH <7, the concentration of H+ is _________ than OH-

Larger, making the solution acidic

At pH >7, the concentration of H+ is _________ than OH-

Smaller, making the solution alkaline

How many times faster does sound travel in water than air?

4 times faster (sound can’t travel in a vacuum (space))

Sunlight has all wavelengths of the visible light, which we see as:

White

Long wavelengths, which are ____, have the _______ penetration

Red, lowest

Short wavelengths, which are______, have the _________ deepest

Blue, deepest

Why do we see the ocean as blue?

Because blue penetrates the deepest and is absorbed last

Seawater consists of many different:

Solutes (ions) of salts

What are the most abundant ions of salts?

Cl- (Chloride), Na+ (Sodium), followed by SO42- (sulfate, the salt of sulfuric acid)

What are trace elements?

Ions very low in concentration, e.g. Fe2+ (dissolved iron), can be crucial for life

What is the average salinity of the ocean?

35 PSU (35g/kg)

What is salinity affected by?

Evaporation and precipitation

The higher the salinity, the higher the:

Density

What is an example of a salt input?

Continental weathering combined with river discharge

What is an example of a salt output?

Burial in sediments

What is residence time?

The amount of time an element stays in the ocean

How can different depth profiles of element concentration be observed?

Depending on how they are affected by biological or chemical processes: bio-unlimited, bio-intermediate, bio-limiting, scavenged

Why does the percentage of gases in the atmosphere and ocean differ?

Has to do with the production/consumption and dissolution behavior of these gases in the ocean

Where and how is oxygen produced in the ocean?

It is produced in the light-penetrated part of the ocean by photosynthesis

Where and how is oxygen consumed in the ocean?

It is consumed by repsiration in the dark (nonphotosynthetic) parts of the ocean

What does carbon dioxide form when it reacts with water and dissolves?

Carbonic acid, bicarbonate, and carbonate

What does the abundance of each carbonate species depend on?

pH, the addition of CO2 leads to more acidity and promotes dissolution of calcium carbonate (such as the shells of animals)

What water masses in the ocean take up a lot of CO2 from the atmosphere before they sink into the deep?

Cold, deep water masses such as the Antarctic deep water

Cold, deep water (high CO2, high pressure) is very corrosive for:

Carbonate shells