Exam 3: CH 5 & 6 Flashcards
Are the properties of a compound different or the same from the properties of the elements that compose it?
different
What is a mixture?
a balloon is filled with a mixture of hydrogen and oxygen gas, the relative amount of hydrogen and oxygen are variable
what is a chemical compound?
the balloon is filled with water, composed of molecules that have a fixed ratio of hydrogen to oxygen
what does the law of constant composition state?
all samples of a given compound have the same proportions of their constituent elements
Who discovered the law of constant composition?
Joseph Proust
What does a chemical formula contain?
symbol for each element and subscript
what do the subscripts in a chemical formula represent?
relative numbers of each type of atom in a chemical compound; they never change for a given compound
chemical formulas list which elements first?
the most metallic
What are polyatomic ions?
groups of elements that act as one, have a charge associated with them
How do we determine the total number of each type of atom in a compound containing a group within parenthesis?
multiply the subscript outside the parenthesis by the subscript for each atom inside the parenthesis
what is a empirical formula?
gives the relative number of atoms of each element in a compound
what is a molecular formula?
gives the actual number of atoms of each element in a molecule of the compound
what are atomic elements?
those that exist in nature with single atoms as their basic units *most elements
what are molecular elements?
they exist as diatomic molecules as their basic unit
what are diatomic molecules?
two atoms of the element bonded together
what are the diatomic molecules?
H2, N2, O2, F2, Cl2, Br2, I2
what are molecular compounds?
compounds formed from two or more nonmetals
what are ionic compounds?
one or more cations paired with one or more anions
what is the basic unit that composes dry ice?
CO2 molecules (molecular compound)
what basic unit composes table salt?
NaCl formula units (ionic compound)
in a chemical formula, the sum of the charges of the positive ions (cations) must always _________ the sum of the charges of the negative ions (anions)
EQUAL
What are type 1 ionic compounds?
contains a metal with an invariant charge - one that does not vary from one compound to another
what are type 2 ionic compounds?
contains a metal with a charge that can differ in different compounds
type 2 metals are found where?
transition metals section
when determining the charge of a metal in a chemical formula, how do we know?
the sum of all the charges must be 0
what are oxyanions?
anions containing oxygen
if there are two ions in the series, how do we label the endings?
the one with more oxygen anions is given the ending -ate and the one with fewer is given the ending -ite
what does the pre-fix hypo mean
less than
what does the prefix per mean
more than
what is the prefix for one
mono
prefix for two
di
prefix for three
tri
prefix for four
tetra
prefix for five
penta
prefix for six
hexa
prefix for seven
hepta
prefix for eight
octa
prefix for nine
nona
prefix for ten
deca
what are the two groups of acids
binary and oxyacids
what are binary acids
one that contains only hydrogen and a nonmetal
what are oxyacids
one that contains hydrogen, nonmetal, and oxygen
how do we name binary acids
hydro-base name of nonmetal + -ic - acid
how do we name an oxyacid ending in -ite
base name of oxyanion + -ous - acid
how do we name an oxyacid ending in -ate
base name of oxyanion + -ic - acid
the information in a chemical formula, along with atomic and formula masses, can be used to what?
calculate the amount of a constituent element in a compound
with atoms, we must use their _______ as a way to count them?
mass
atoms are too what to count individually
too small and too numerous
the chemist’s dozen is called _____?
mole (mol)
1 mol =
6.022 x 10^23
what is avogrado’s number?
6.022 x 10^23
the atomic mass unit (amu) is described as what?
one-twelfth of the mass of a carbon-12 atom
the molar mass of any element is equal to what?
the atomic mass of that element expressed in atomic mass units
the molar mass of a compound in grams per mole is numerically ______ to the _____ _____ of the compound in amu
equal, formula mass
the formula mass for a compound is the _____ of the atomic masses of all the atoms in a chemical formula
sum
how do we find the mass percent composition?
mass % of element x = mass of x in a sample of the compound/mass of the sample of the compound x 100
an empirical formula gives what?
the smallest whole-number ratio of each type of atom in a compound, not the specific number of each type of atom in a molecule
what is molecular formula for compounds?
CH2O x n
how do we solve for n
n = molar mass/empirical formula molar mass
