Ocean Chemistry: Solutions
LA Charter School Science Partnership
15 October 2011
Nick Klein
Today’s Talk
• Intro & Biography
• Part 1: Chemistry review, phases of matter
• Part 2: Chemical solutions
• Part 3: Solutions in the ocean context
About Me
• Third year PhD student in
Earth Sciences
• BA Biology and Chemistry
from Augustana College, SD
• I study global impacts of
marine trace chemistry
• Thesis research: production
of marine halocarbons
Field sampling on Lake Tahoe
Today’s Talk cont’d
• I’ve split this talk into three (roughly) even
parts. We will take a brief (2-3min) break
between sections. Please feel free to take
notes, handle the props on the table at the
front of the room, think of questions for
after the talk, etc.
Sergio Sañudo-Wilhelmy, my PhD mentor
Part 1: Basic chemistry review
• What is the basic unit of chemistry?
– An atom
• How do we define an atom?
– Smallest unit of a chemical element that still
has all the unique characteristics of that
element
– Indivisible by any chemical means
Part 1: Basic chemistry review
• Atoms are composed of a
nucleus and orbiting
electrons
• Nucleus contains protons
and neutrons
• Electrons are negatively
charged, protons positive.
Neutrons are not charged
(neutral).
Part 1: Basic chemistry review
• The identity of an atom is based on the
number of protons it has. This is called
the atomic number
Part 1: Basic chemistry review
Part 1: Basic chemistry review
• The identity of an atom is based on the
number of protons it has. This is called
the atomic number
• Carbon has an atomic number of 6
(6 protons)
• Oxygen has an atomic number of 8
(8 protons)
Part 1: Basic chemistry review
• An electron has almost
no mass (weighs almost
nothing)
• Protons and neutrons
have the same mass,
each weighs 1 atomic
mass unit (1 amu)
• Atomic mass is weight (in amu) of an atom
and is therefore equal to protons + neutrons!
Part 1: Basic chemistry review
Part 1: Basic chemistry review
• Carbon has an atomic mass of 12amu
6 protons + 6 neutrons = 12
• Oxygen has an atomic mass of 16amu
8 protons + 8 neutrons = 16
• Since electrons weigh nearly nothing,
almost all of the mass of an atom is in the
nucleus!
Part 1: Basic chemistry review
• Atoms and molecules are mostly empty
space!
A single pea
(nucleus)
Part 1: Basic chemistry review
• Atoms are tiny!
• How many molecules of water are in my
flask?
• Answer: about 600 billion trillion, or
600,000,000,000,000,000,000,000
molecules of water!
Part 1: Basic chemistry review
• The kinetic molecular theory of matter:
We can describe the behavior of matter
based on what we know about how the
individual molecules are moving.
Part 1: Basic chemistry review
• Three phases of matter: solid, liquid, gas
• Solid – slowest movement of molecules,
just vibrating
• Liquid—molecules moving enough to be
able to flow over and around each other
• Gas—molecules moving very rapidly, fill
the available space
Part 1: Basic chemistry review
• Three phases of matter: solid, liquid, gas
• Solid – slowest movement of molecules,
just vibrating
• Liquid—molecules moving enough to be
able to flow over and around each other
• Gas—molecules moving very rapidly, fill
the available space
Part 1: Basic chemistry review
• Solid—fixed shape and volume, molecules
cannot move
• Liquid—no fixed shape, but volume stays
the same. Molecules can flow.
• Gas—no fixed shape OR volume,
molecules spread to fill the available
space.
Part 1: Basic chemistry review
http://www.youtube.com/v/akUuFsH4B1c
Part 1: Basic chemistry review
Counting molecules- we use a special unit
called the “mole”
= 6.02 x 1023 molecules or atoms
There are 6.02 x 1023 protons in one gram of protons
(or neutrons)
• This allows us to easily convert from amu
on the periodic table into molecules of a
substance!
Part 1: Basic chemistry review
Break
Part 2: Solutions
• What is a solution?
• How do we define a chemical solution?
A mixture of two or more substances
which are dispersed homogenously on a
molecular level.
Part 2: Solutions
• Solvent- the substance that is in greater
quantity, does the dissolving, usually a
liquid
• Solute- the substance that is dissolve,d
usually in a lesser quantity, can be solid,
liquid, or gas
• How about your morning coffee (or tea, or
soda…)?
Part 2: Solutions
• Why don’t oil and vinegar mix? Why do
alcohol and water mix?
• Let’s examine the structure of some of
these molecules.
Part 2: Solutions
Part 2: Solutions
Part 2: Solutions
• The answer is polarity
• Some molecules have their electrons
unevenly distributed, giving them a more
negative and a more positive end
• Nonpolar molecules have electrons evenly
distributed throughout
Part 2: Solutions
Part 2: Solutions
• Electronegativity – some elements are
“greedy” and want electrons more than
others. They don’t like to share.
• Oxygen is greedy!
Part 2: Solutions
Part 2: Solutions
Part 2: Solutions
• Why don’t oil and vinegar mix? Why do
alcohol and water mix?
• Let’s examine the structure of some of
these molecules.
Part 2: Solutions
+
+
+
-
+
-
Part 2: Solutions
Part 2: Solutions
LIKE DISSOLVES LIKE!
Part 2: Solutions
Part 2: Solutions
• Why do we use soap to wash our dishes?
• How does soap work?
Part 2: Solutions
• Soap molecules are surfactants. They
have a charged (polar) head and a
relatively uncharged (nonpolar) “tail,” so
they can bridge the gap between water
and grease! Water is then able to
dissolve the grease or oils. This is called
an emulsion.
• How might this be important for cleaning
up oil spills?
Part 2: Solutions
Part 2: Solutions
Part 2: Solutions
• Hydrogen bonding is a related concept
• Since polar molecules have oppositely
charged ends, they can attract each other
and form loose chemical bonds
• This is especially important in water!
Part 2: Solutions
Break
Part 3 – Ocean Context
• Let’s brainstorm!
• Why is the chemistry of the oceans
important?
Part 3 – Ocean Context
• Cover 75% of Earth’s surface
• About 50% of all life on Earth lives in the
oceans (if it weren’t for algae, we wouldn’t
have oxygen to breathe, too!)
• They moderate our climate and weather
by storing and releasing heat
Part 3 – Ocean Context
• The story of ocean chemistry is the story
of aqueous solutions (solutions with water
as the solvent)
• Water has many unique properties
because of the chemistry we have
discussed
• How many can we come up with?
Part 3 – Ocean Context
• Water exists in three distinct states of
matter in typical Earth conditions – water
vapor (steam, clouds), liquid water, and
ice
• Water is a great solvent (3.5% salt)
• Water has a high heat capacity
• Solid water (ice) is actually less dense
than liquid water and floats
Part 3 – Ocean Context
Before you go…
• Think about this scenario and come up
with a description (based on the kinetic
molecular theory of matter) of what is
happening on a macro (large) scale and
on the molecular level:
• An iceberg breaks loose in the Arctic and
begins to float south into warmer waters.