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