Anatomy- Chapter 2
mixture
a combination of elements or compounds that are physically blended together but not bound by chemical bonds
surface tension
a measure of the difficulty of stretching or breaking the surface of a liquid.
chemical element
all forms of matter- both living and nonliving- are made up of a limited number of building blocks
metabolism
all the chemical reactions occurring in the body
organic compounds
always contain carbon, usually hydrogen, and always have covalent bonds.
oxidation-reduction reactions
always parallel; when one substance is oxidized, another is reduced at the same time.
free radical
an atom or group of atoms with an unpaired electron in the outermost shell.
Ion
an atom that has a positive or negative charge because it has unequal numbers of protons and electrons
electrolyte
an ionic compound that breaks apart into positive and negative ions in solution
Isotopes
atoms of an element that have different numbers of neutrons and therefore different mass numbers.
colloid
differs from a solution mainly because of the size of its particles
products
ending substances--two molecules of H2O
potential energy
energy stored by matter due to its position
chemical bonds
forces that hold together the atoms of a molecule or a compound
reduction
gain of electrons; reduced substance gains energy
energy
is the capacity to do work
overall reaction
may either release energy or absorb energy
water
most important and abundant inorganic compound in all living systems.
Anion
negatively charged atom
Cation
positively charged ion
subatomic particles
protons neutrons and electrons
oxidation
refers to the loss of electrons; substance releases energy
double covalent bond
results when two atoms share two pairs of electrons
atoms
smallest units of matter
For chemical reactions to occur...
some particles of matter--especially large molecules--not only must collide with sufficient force, but they must hit one another at precise spots. A catalyst helps to properly orient the colliding particles.
reactants
starting substances- two H2 and one O2
compound
substance that contains atoms of two or more different elements
mass number
sum of protons and neutrons
temperature influencing the chance that a collision will occur and cause a chemical reaction
temperature goes up, particles move more rapidly -the higher the temperature of matter, the more forcefully particles will collide, and the greater the chance that a collision will produce a reaction.
atomic mass
the average mass of all its naturally occurring isotopes
kinetic energy
the energy associated with matter in motion
Example for potential and kinetic energy
the energy stored in water behind a dam or in a person poised to jump down some steps is potential energy. When the gates of the dam are opened or the person jumps, potential energy is converted into kinetic energy
Ionic Bond
the force of attraction that holds together ions with opposite charges
valence shell
the number of electrons in the outermost shell
electronegativity
the power to attract electrons itself
Ionization
the process of giving up or gaining electrons
reversible reaction
the products can revert to the original reactants.
polar covalent bond
the sharing of electrons between two atoms is unequal--the nucleus of one atom attracts the shared electrons more strongly than the nucleus of the other atom.
nonpolar covalent bond
two atoms share the electrons equally one atoms does not attract the shared electrons more strongly than the other atom.
triple covalent bond
two atoms share three pairs of electrons
covalent bond
two or more atoms share electrons rather than gaining or losing hem
Octet Rule
two or more atoms that interact in ways that produce a chemically stable arrangement of either valence electrons for each atom.
inorganic compounds
usually lack carbon and are structurally simple.
single covalent bond
when two atoms share one electron pair
molecule
when two or more atoms share electrons
anabolism
-all synthesis reactions that occur in the body are referred to as anabolism -usually endergonic because they absorb more energy than they release
Law of conservation of energy
-although energy can be neither created nor destroyed, it may be converted from one form to another.
Dalton
-atomic mass unit (also known as) -standard unit for measuring the mass of atoms and their subatomic particles
Catalysts
-chemical compounds that speed up chemical reactions by lowering the activation energy needed for a reaction to occur. -most important catalysts in the body are enzymes
exchange reactions
-consist of both synthesis and decomposition reactions
dehydration synthesis reaction
-de= down, hydra= water -a water molecule is one of the products formed. -two smaller molecules join to form a larger molecule
Catabolism
-decomposition reactions that occur in your body -usually exergonic because they release more energy than they absorb.
solvent
-dissolves another substance (solute) -ex. water
endergonic reaction
-end- within -absorb more energy than they release
exergonic reaction
-ex-out -release more energy than they absorb
chemical energy
-form of potential energy that is stored in the bonds of compounds and molecules. -total amount of energy present at the beginning and end of a chemical reaction is the same.
Thermal properties of water
-heat capacity -heat of vaporization
hydroplysis
-lysis= to loosen or break apart -enable dietary nutrients to be absorbed into the body
hydrophobic
-molecules that contain mainly nonpolar covalent bonds. -phobic= fearing -they are not very water soluble -examples are animal fats and vegetable oils
concentration of particles
-more particles of matter present in a confined space, the greater the chance that they will collide. -concentration of particles increases when more are added to a given space or when the pressure on the space increases, which forces the particles closer together so that they collide more often.
chemical reaction
-occurs when new bonds form or old bonds break between atoms -foundation of all life processes
hydrogen bond
-result from attraction of oppositely charged parts of molecules -weak compared to covalent and ionic bonds -happens when a partially negative charged hydrogen atom attracts a partially positive charged atom
hydrophilic
-solutes that are charged and contain polar covalent bonds -^they dissolve easily in water -examples sugar and salt -Hydro=water, ophilic= loving
decomposition reactions
-split up large molecules into smaller atoms, ions, or molecules.
solute
-substance being dissolved -ex. sugar
In a chemical reaction...
-the total mass of the reactants equals the total mass of the products -the number of atoms in each element is the same before and after the reaction
synthesis reaction
-when two or more atoms, ions, or molecules combine to form new and larger molecules. -synthesis means "to put together"
activation energy
-a sufficiently forceful collision can disrupt the movement of valence electrons, causing an existing chemical bond to break or a new one to form. -the collision energy needed to break the chemical bonds of the reactants