Bio U3 Atoms, Water, pH (Biochemistry Quiz 1)

Review for quiz on 10/18.

atom

single particle of an element of the periodic table, such as sodium, oxygen, or carbon

molecule

more than one atom bonded together, such as water (H2O), gaseous oxygen (O2) or salt (NaCl)

compound

molecules that contain at least two types of atoms, such as water (H2O) or salt (NaCl)

positive charge

protons, +

negative charge

electrons, -

nonpolar molecule

molecule with an even distribution of electrons (equal sharing), such as methane (CH4)

ionic bond

bond formed by one atom donating/giving an electron to another atom, such as Na+/Cl-

covalent bond

bond formed by two atoms sharing electrons

polar molecule

molecule with uneven sharing of electrons (such as H2O)

proton

particle in an atom with a positive charge

neutron

particle in an atom with a neutral charge

electron

particle in an atom with negative charge

hydrogen bonds

attractions between partial positive and partial negative charges on polar molecules, such as attractions between water molecules; represented by a dotted line

surface tension

phenomenon that allows insects such as water striders to skate on top of water; caused by strong cohesion between water molecules

cohesion

attraction of water molecules to other water molecules

adhesion

attraction of water molecules to other kinds of molecules such as glass

capillary action

phenomenon where water can move up a thin tube against gravity using adhesion and cohesion, allows water to move up a plant stem

boiling point

temperature at which a substance goes from liquid to gas, such as from liquid water to water vapor

specific heat

the heat required to raise the temperature of the unit mass of a given substance by a given amount (usually one degree)

pH

measure of how acidic/basic a solution is

acidic

0.0-6.9 on the pH scale, higher concentration of hydrogen ions, [H+], such as lemon juice or vinegar

basic

7.1-14.0 on the pH scale, higher concentration of hydroxide ions, [OH-], such as bleach or ammonia

neutral

7.0 on the pH scale, pure water