Chapter 3 Flashcards
enantiomers
one of two compounds that are mirror images of each other and that differ in shape due to the presence of an asymmetric carbon.
mass number
the total number of protons and neutrons in an atoms nucleus.
atom
the smallest unit of matter that retains the properties of an element.
heat
thermal energy in transfer from one body of matter to another.
van der walls interactions
weak interactions between molecules or parts of molecules that result from transient (lasting only for a short time) local partial charges.
solution
a liquid that is a homogenous mixture of two or more substances.
chemical reactions
the making and breaking of chemical bonds, leading to changes in the composition of matter.
evaporative cooling
the process in which the surface of an object becomes cooler during evaporation, a result of the molecules with the greatest kinetic energy changing from the liquid to the gaseous form.
polar covalent bond
a covalent bond between atoms that differ in electronegativity. the shared electrons are pulled closer to the more electronegative atom, making it slightly negative and the other atom slightly positive.
chemical bonds
an attraction between two atoms, resulting from a sharing of outer-shell electrons or the presence of opposite charges on the atoms. the bonded atoms gain complete outer electron shells.
isotopes
one of several atomic forms of an element, each with the same number of protons but a different number of neutrons, thus differing in atomic mass.
covalent bond
a type of strong chemical bond in which two atoms share one or more pairs of valance electrons.
kilocalorie
a thousand calories; the amount of heat energy required to raise the temperature of 1 kg of water by 1 degree celsius.
ionic compounds
a compound resulting from the formation of an ionic bond; also called a salt.
compound
a substance consisting of two or more different elements combined in a fixed ratio.
ocean acidification
the process by which the ocean’s pH is lowered (made more acidic) when excess carbon dioxide dissolves in seawater and forms carbonic bonds.
molecule
two or more atoms held together by covalent bonds.
hydroxide ion
a water molecule that has lost a proton; written as OH subscript minus.
double bond
a double covalent bond; the sharing of two pairs of valance electrons by two atoms.
valance shell
the outermost energy shell of an atom, containing the valance electrons involved in the chemical reactions of that atom.
anion
a negatively charged atom
valance
the bonding capacity of a given atom; the number of covalent bonds an atom can form, which usually equals the number of unpaired electrons in its outermost (valance) shell.
hydrogen ion
a single proton with a charge of 1-plus. the dissociation of a water molecule leads to the generation of a hydroxide ion (O charge of 1-minus) and a hydrogen ion (charge of 1-plus); in water, the hydrogen ion is not found alone but associates with a water molecule to form a hydronium ion.
