A&P Ch. 2

Water solvent

Substances dissolved in water: 1. solvent - medium that atoms are dispersed in 2. solute - dispersed substances 3. aqueous solutions- water is the solvent

acid

a substance that increases the concentration of hydrogen ions (H+) in a water solution when dissociation occurs; strong acids dissociate completely like HCI

Water is reactive

allows chemical reactions to occur within it

salt

an ionic compound containing any cation except a hydrogen ion, and any anion except a hydroxide ion

covalent bonds

involves the sharing of electrons between atoms creating a bond

What is Stomach Acids pH? (test question)

pH 1 - 2

mass

the amount of material in matter, mass equals wirght

acidity

Acidic solutions have a higher concentration of H+ ions than OH+ ions giving it a pH below 7

Define pH, and explain how the pH scale relates to acidity and alkalinity.

The pH is a measure of the concentration of hydrogen ions in fluids. Acid and base concentrations are measured in pH, which is the negative logarithm of hydrogen ion concentration, expressed in moles per liter. On the pH scale, 7 represents a neutral solution; values below 7 indicate acidic solutions, and values above 7 indicate basic (alkaline) solutions.

buffer system

chemicals that minimize changes in pH by reacting with strong acids or strong bases and changing them into substances that will not drastically change pH

Third Energy Level

contains a maximum number of 8 electrons

Second Energy Level

contains a maximum of 8 electrons

polar covalent bond

demonstrate unequal sharing of electrons because elements may differ in how strongly they attract electrons. These bonds are weaker than "nonpolar covalent bonds"

ionization

dissociation of breaking of bonds that separate anions from cations that can now take part in other chemical reactions

nonpolar covalent bond

each atom in a molecule has an equal sharing of electrons

electron cloud

electrons orbit the nucleus in circular shells called energy levels; they stay orbiting around the nucleus because of their attraction to protons, opposite charges are drawn together

ionic bond

form salts, acids and bases

Hydrogen bonds

hydrogen has a special property in that while it is sharing its electron with another element, its proton maintains a light positive charge. allowing it to create "weak bonds" with other slightly negatively charged atoms

First Energy Level

innermost level; can contain a maximum of 2 electrons

ionic bonds

involves the loss of one or more electrons by one atom and the gaining of the electrons by another atom, a bond is created by the electrical attraction between atoms

Anion

ion with a negative charge; having more electrons than protons (Cl-, SO4-2 sulfate, and HCO3- bicarbonate)

cation

ion with a positive charge; having more protons and electrons (Na+, Ca+ 2, K+, Fe+ 2 and Mg+ 2)

PH

negative logarithm of the hydrogen ion concentration in moles per liter; pure water is - (-7) or 7 because [H+] = 1 x 10^ -7

Atomic number

number of protons in an atom. Each atom is identified by the number of protons found in the nucleus The number of electrons equals the number of protons in an atom. This makes the atom electrically neutral

What is Intracellular fluids pH? (test question)

pH 6.8

What is bloods pH? (test question)

pH 7.45

water is a lubricant

prevents friction where surfaces meet and move

mass number

total number of protons and neutrons in the nucleus

atoms

the smallest stable units of matter, the building blocks of all living and non-living things. Atoms are arranged into molecules and compounds

What is the significance of pH in physiological systems?

If the body is to maintain homeostasis and thus health, the pH of different body fluids must remain within a fairly narrow range.

Base

a substance that removes hydrogen ions (H+) in a water solution by releasing hyrdoxyl ions (OH-) to form water molecules with the hydrogen; a strong base dissociates completely like NaOH

ion

an atoms that has an unequal number of electrons and protons creating a charge (Na^+) and (Cl^-)

free radical

an ion or molecule containing unpaired electrons in the valence energy level. These free radicals are destructive and promote the aging process

matter

anything that takes up space and has mass

Decomposition

bonds are broken changing a larger molecule into 2 or more smaller ones, releases kinetic energy; metabolic breakdowns in the body are referred to as catabolism (digestion of food)

synthesis reactions

bonds are formed to make a new compound, requires energy, metabolic formation of bonds in the body are referred to as anabolism

Valence electrons

electrons in the outermost energy level. Atoms become 'stable' when the valence shell contains the maximum number of valence electrons

negative charge

if there are more "electrons" than there are "protons" the charge will be negative

positive charge

if there are more "protons" than there are "electrons" the charge will be positive

Antioxidant

molecules that safely interact with free radicals, neutralizing them before vital molecules are damaged

element

pure substances composed of atoms of only one kind

pH Scale

ranges from 0 (extremely acidic) --> 14 (extremely basic)

Alkaline (basic)

solutions have a higher concentration of OH- ions than H+ ions giving it a pH above 7

chemical bond

the force that holds atoms together after a reaction has occurred; force of attraction between positive and negative charges

Valence Shell

the outermost energy level forming the 'surface' of the atom