Cheatography
https://cheatography.com
First term chemistry for first year of aerospace engineering.
This is a draft cheat sheet. It is a work in progress and is not finished yet.
Isotopes of Hydrogen
₁¹H→Deuterium (²₁H)→Tritium (³₁H) |
Mol: amount of substance SI
Nₐ=6,022*10²³entities/mol |
mass of 1 mol of substance=its atomic mass (uma), taken as grams |
Rydberg relation
only a limited number of energy values are available to excited gaseous atoms
The Bohr Atom
First postulate |
atom= nucleus(positivecharge and miuch of the system mass) +e⁻ moving in circular orbits around it |
Fe=Fc⟶r=(Ze²)/(4πε₀m𝜈²) |
Second postulate |
The e⁻ has only a fixed set of stationary states, as long as it remains in the same orbit, its energy is constant and no energy is emitted |
Third postulate |
An e⁻can pass only from one allowed orbit to another emitting or absorvig quanta(fixed discrete quantities of energy) |
Heisenberg's uncertainty principle
De Broglie's wave-particle duality
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Law of conservation of mass
Matter cannot be created nor destroyed |
mass reactants=mass products |
Law of definite proportions
A chemical compound always contains exactly the same proportion of elements by mass |
The modern atom
Atomic Number=Z=protons
Mass number=A=protons+neutrons
Electromagnetic spectrum
c=λ*𝑣 |
γ rays |
[10⁻¹⁵,10⁻¹¹]m |
X rays |
[10⁻¹³,10⁻⁹]m |
U.V. |
[10⁻⁹,390*10⁻⁶]m |
Visible |
[390,760]nm |
Infrarred |
[760*10⁻⁶,10⁻³]m |
Microwave |
[10⁻³,10⁻¹]m |
Radio |
[10⁻²,10⁴]m |
the given values are for λ
Atomic spectrum of Hydrogen
Balmer experimentally found a frequency formula to define H spectral lines |
𝜈=3,288110¹⁵(1/2-1/n²) s⁻¹ |
The photoelectric effect
Einstein postulated that light is not a wave but a collection of discrete wave packets (photons)
The Zeeman effect
spectral lines are split in the presence of a magnetic fild |
the split was proportional to the applied magnetic field |
Quantum number
n (principal quantum number) |
1,2,...,n |
l (angular momentum number) |
[0,...,n-1] |
m (magnetic quantum number) |
[-l,...,l] |
s (spin number) |
[-1/2,1/2] |
Pauli Exclusion Principle
In an atom two electrons cannot have the same quantum numbers |
Planck's formula
the quantum energy is proportional to the frequency of the emitted radiation, the energy of a system changes in specific quanta.
h=6,626*10⁻³⁴
Orbitals
Description of the probability of finding the electron in the space |
high electronic charge density |
Multielectron atoms
Different penetrating and shielding properties of the orbitals |
Zeff=Z-σ |
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