AP Chemistry - Atomic Structure and Properties

Avogadro's Number

Avogadro's Number

6.022 x 10^23 particles per mol

Why do different substances have the same amount of particles but different masses?

The particles in each sample are different

The average mass in amu of one atom, molecule, or formula of its substance its equal to its

molar mass in grams

chemical stoichiometry

quantities materials consumed and produced in chemical reactions

The formula mass is equal to the

molar mass

what are the units for molar mass

g/mol

what are the units for formula mass

u

Molar mass is used to convert quantities between mass units and

counts units

mass spectroscopy

technique used to find isotopes and their relative abundance

Law of Definitie Proportions

the ratio of the constituent elements in a pure sample is always the same

Empirical Formula

lowest whole number ratio of atoms of the elemnts of a compound

Chemical/Molecular Formula

actual mole ratio inin compound

mixture

more than one pure substance with variable composition

electron charge

-1.602 x 10^-19 coulomb

1 pound to grams

453.6 g

1 quart to cubic decimeters

0.9464 dm^3

1 quart to liters

0.9464 L

1 inch to cm

2.54 cm

mole

amount of substance that contians the number of particles as atoms in exactly 12 grams of carbon-12

stoichiometry

the calculation of the amount of one substance in a chemical reaction using another substance

limiting reactant

the reactant that is used up first in a reaction

theoretical yield

maximum amount of product formed

actual yield

actual amount of product formed in a reaction

percent yield

the actual yield over the theoretical yield

solutions

homogenous soluations composed of a solute and a solvent

solute

substance present in smaller amount

solvent

substance present in larger amount

concentration

amount of a solute dissolved in the solvent

molarity (M)

moles of solute per liter of solution

electromagnetic spectrum

radiant energy composed of various rays

frequency (v)

number waves that pass a point per second

wavelength (λ)

distance between two identical points on a wave

amplitude

height of a wave

what is amplitude related to in a wave?

intensity of the wave

equation for the energy associated with a certain frequency of light

E=hv

Planck’s constant (h)

6.626 x 10^-34 J s

speed of light (c)

2.998 x 10^8 m s^-1

equation for the speed of light

c=vλ

simple wavelength equation

λ=hc/E

equation relating mass and wavelength

λ=h/mv

equation for the momentum of a particle

p=mv

line spectrum

a series of fine colors that are usually vien off when the vapor of an element is heated

quantized

there are only distinct energies associated with an atom

ground state

lowest energy state of an atom

excited state

higher energy state of an atom

quantum

amount of energy absorbed or emitted by an atom

equation for an energy level for a hydrogen’s electron

En = -2.179 x 10^-18/n^2 joule

equation for energy difference between any two energy levels

∆E=-2.18=10^-18 J (1/n^2final - 1/n^2initial)

wave function

an atomic orbital; describes the electron’s motion

electron cloud

the area in which finding an electron is high

how is the electron cloud volume found?

squaring the wave function

principal quantum number (n)

an atom’s shell; describes the energy and distance of an orbital from its nucleus

angular momentum qunatum number (l)

subshells; describe the shape of an orbital

magnetic quantum number (ml)

orientation of the orbital around the nucleus

What are possible values for the principal quantum number?

positive integers

What are possible values of the angular momentum quantum number?

0 to (n-1)

What are possible values of the magnetic quantum number?

-l to +l

photoelectrons spectroscopy (PES)

technqiue where photons remove an electron frmo an atom; related binding energy to the number of electrons

spin quantum number (ms)

spin of the electron

What are the possible values of the spin quantum number?

-1/2 to +1/2