unit 3 - chem math Flashcards
mole
- a mole represents a number
- 1 mole = 6.02 x 10^23
mass of an atom is in
AMU
mass of a mole of atoms is in
grams
when converting moles to anything
MOLEtiply
when converting TO moles
divide
gram formula mass
- mass of 1 mole
- the mass of a substance expressed in grams instead of AMU
molar mass
gfm
% composition
the amount of an element in a compound expressed as a %
hydrate
is a salt that has a definite amount of water molecules embedded into its structure
anhydrous salt
what we are left with after heating a hydrate and the water evaporates
molecular formula
- true formula for a compound
- exact number of atoms of each element in the compound
empirical formula
simplest whole # ratio of compound
to find the ratio of molecular to empirical…
molecular mass/empirical mass
1 mole of any gas occupies
22.4 liters at STP
stoichiometry
the area of chem math where we take a balanced chemical equation to use mole ratios (coefficients) to make predictions about the products of the reaction
1 step stoichiometry problems are
- mole to mole
- liter to liter
limiting reagent problems
a reactant is in short supply
hint about determine LR problems
LR problems will give you the masses of each reactant
elements
made of one kind of atom
compound
substance made of two or more elements that are chemically combined
ionic compounds
form between positive and negative ions
when do u use roman numerals
always use a roman numeral to designate the charge on metals with multiple oxidation states
molecules
made of 2 NON METALS held together by covalent bonds
covalent bonds prefix vowel rule
drop the o or a in the prefix name if the element begins with a vowel
ammonia
NH3
hydrogen peroxide
H2O2
subscripts
number written below and to the right of a chemical symbol, shows the number of atoms of each element
chemical formula
a shorthand notation for a compound or diatomic element
chemical equation
a representation of a chemical reaction where the reactants and products are expressed in formulas