Study Guides

CHAPTER 2 THE CHEMICAL CONTEXT OF LIFE
MATTER AND ITS DIFFERENT STATES
 Matter is anything that has mass and takes up space
o Anything that you can and cannot see
o Everything that is not empty space
 States of matter
o 3 main forms on earth for biological organisms
o Can depend on pressure, temp, and if its interaction with other forms
o Liquid: No regular arrangement of particles that takes up the shape of its
container. The particles stick closely together and can be penetrated
o Solid: Regularly arranged particles that help make up a specific shape or
arrangement. Its particles are close together where it can’t be penetrated
o Gas: Tend to take on the shape of its container that they’re placed in. Its particles
are placed far apart which makes it easier to penetrate
 Matter consists of chemical elements in pure forms and also in compounds which are a
combination of elements
THE PROCESSES MATTER CAN USE TO CHANGE ITS STATE
 Evaporation: Liquid to gas
o EX: Gas
 Condensation: Gas to a liquid
o EX: water droplets on a car
 Melting: Solid to a liquid
o EX: Melting ice
 Freezing: Liquid to a solid
o EX: Freeze water
 Sublimation: Solid to a Gas
o EX: Ice in a freezer that is placed in for too long
 Deposition: Gas to a Solid
ELEMENTS VS COMPOUNDS
 Compounds: A substance that consistent of two or more different elements that are
combined in a fixed ratio.
o Distinguishing Features: contains different elements in definite quantities and
proportions by chemical bonds
o Ability to breakdown: Can be separated into simpler substances by chemical
methods
o Type #: endless amounts of compounds
o Properties: Depend on its atoms and how they are bonded together
 When elements combine, individual properties of the atom are lost and
new properties are created from the elements it is composed of
o Represented: by Formula
o Examples: Sodium (Na) + Chlorine (Cl) = Sodium Chloride (NaCl) 1:1 ratio
 Elements: A pure substance that cannot be broken down to other substances by chemical
or physical means. Simplest Form.

, o Distinguishing Features: Each element has their own atomic structure and
chemical properties as a result of their unique arrangement of subatomic particles.
They can be distinguished by their atomical number.
o Classified: Classified by their properties
 Boiling Point
 Melting Point
 Density
 Reactivity
o Ability to breakdown: Cannot be broken down into a simpler substance by
chemical reactions
o Type #: 92 naturally occurring elements with 117 total is being observed
o Represented: Using atomic symbols
o Examples: Iron (Fe) or Copper (Cu)
ESSENTIAL ELEMENTS
 Elements needed by an organism to live a healthy life
o Humans = 25 Elements needed to live
o Plants = 17 elements needed to live
 Out of 92 naturally occurring elements, only 20-25% are essential for organisms to use
and reproduce
 Same amongst all different organisms but they do have different variations since some
can be toxic for different organisms
 Elements that make up 96% that are essential for living matter
o Oxygen (O)
o Carbon (C)
o Hydrogen (H)
o Nitrogen (N)
 Elements that make up 4% essential for an organism’s mass
o Calcium (Ca)
o Phosphorous (P)
o Potassium (K)
o Sulfur (S)
TRACE ELEMENTS
 Required by organisms in only small amounts and only in minute quantities
o Can be needed by all forms of life while certain species only require some
o Nitrogen Deficiency
o Iodine deficiency
 Have a mass of at least 0.01%
 Required in amounts less than 100 per day
 Elements
o Iron (Fe): A trace element that is required by all organism
o Arsenic (As): Naturally occurring element that is toxic to most organism
 Trace elements that are required for only some
o Vertebrates for gland activity = Iodine (I)
 Primary Function
o Catalyze in enzyme systems