WVU Chemistry 115 Formulas

Density=

mass/volume

Temperature Kelvin=

Temperature in Celsius + 273.15

Temperature Farenheit=

(1.8)(temp celcius) +32

law of conservation

mass of reactant= mass of product

law of definite proportions

a given compound always contains exactly the same proportion of elements by mass

law of multiple proportions

if two or more different compounds are composed of the same two elements, then the ratio of the masses of the second element combined with a certain mass of the first element is always a ratio of small whole numbers

mass number =

protons + neutrons

ions

positively and negatively charged atoms

isotopes

Atoms of the same element that have different numbers of neutrons

number of neutrons=

mass number - atomic number

atomic mass (atomic weight)

The average mass of all the isotopes of an element

(decimal fraction x mass of isotope #1)

atomic number

the number of protons in the nucleus of an atom

mass number

the sum of the number of neutrons and protons in an atomic nucleus

naming metal ions

add -ion

naming nonmetal ions

take on the stem of the name of the element followed by the suffix "-ide" plus "ion"

-Acetate

C2H3O2-

-Carbonate

CO3 2-

-Hydrogen carbonate or bicarbonate

HCO3-

-Nitrite

NO2-

-Nitrate

NO3-

-Phosphate

PO4 3-

-Phosphite

PO3 3-

-Chromate

CrO4 2-

-Chlorate

ClO3-

-Perchlorate

ClO4-

-Sulfate

SO4 2-

-Sulfite

SO3 2-

-Hydrogen Sulfite

HSO3-

-Hydroxide

OH-

-Cyanide

CN-

-Permangantate

MnO4-

-Ammonium

NH4+

-Dichromate

Cr2O7 2-

-Chlorite

ClO2-

-Peroxide

O2 2-

per

indicates one more oxygen atom than the oxyanion ending in -ate.

hypo

indicates one oxygen atom fewer than the oxyanion ending in -ite

cation + anion

name of cation + base of anion + ide

4 transitional metal exceptions for charges

Zn2+ , Cd2+ , Sc3+ , Ag+

naming transition metals

Metal Name (Roman Numeral) + Non-Metal-ide

naming two nonmetals (molecular)

prefix + name of first element + prefix + base name of second element +ide (mono, di, tri)

What indicates an acid

H as first element

Binary acids have H+ cation and nonmetal anion. •

Oxyacids have H+ cation and polyatomic anion

How to name binary acids

hydro_____ic acid (example HBR hydrobromic acid)

how to name oxyacids

-ate = -ic acid (ate something icky)

-ite = -ous acid

how do you calculate molar mass

add up the atomic mass (multiply by coefficients and subscripts if needed)

define a mole

the amount of a substance that contains as many particles as there are atoms in exactly 12g of carbon-12

Avagodro's number

6.022 x 10^23 anythings = 1 mole of anythings

molar mass

the mass of one mole of a pure substance (g/mol)

(Adding all atomic masses)

key stoichiometry for compounds...

grams to moles (use molar mass)

moles to molecules/atoms (avogadro's number)

moles of compound to moles of individual element (ratio)

calculating mass percent

Mass percent of element X = mass of element X in 1 mol of compound/ mass of 1 mol of the compound X 100%

(Average = x * m¹+ (1-x)m²)