Chemistry Final Flashcards
You got this baby!!
Isotopes
A= (atomic mass)(natural abundance)+(atomic mass)(natural abundance) [4.4% –> 0.44]
Ionic vs. Molecular
Ionic: [Metal + Nonmetal] High melting point & conductive
Molecular: [2 Nonmetals] Low melting point & not conductive
Anion vs. Cation
Anion [ ]- Adding a valence electron Cation [ ]+ Minus a valence electron
In an ionic compound, Metals are ___ and Non-metals are ___
Metals are cations (+)
Non-metals are anions (-)
*Cations always come first
The more shared electrons, the _____ + ____ the bond length is
The more shared electrons, the shorter and stronger the bond length is
When drawing cation/anion Lewis structures, pls remember to show
CHARGE
Steps to Building Lewis Structures
- Count v.e.
- Least electronegative atom in the middle
- Satisfy HONC + all Octets
- Are any exceptions applicable?
- Any Resonance
- Use formal charge to determine best Structure
Valence Shell Expansion
Elements in period 3 can fit more than octet in valence
Formal Charge
(V.E. of atom) - (1/2 of V.E. shared w/element) - (V.E. on element) = FC
Formal Charge (Choosing LS)
Most neutral charge should always be in the middle, no like charges next to each other
The molecule with the lowest charge state is the ideal molecule
Linear
2 bonds (not counting lone pairs) 180 degrees
Trigonal Planar
3 bonds (120)
Tetrahedral
4 bonds (109.5) (one dashed, one triangle)
Trigonal Bipyramidal
5 bonds (90, 120) (one dashed, one triangle)
Octahedral
6 bonds (90) (2 dashed, 2 triangle)
Angles are smaller than the ideal angle when…
When there are lone pairs on one side of a molecule being “fat” & taking up all the space, therefore crowding bonding groups on the other side. Double bonds create the same effect.
However symmetrical lone pairs cancel out and do not crowd
With resonance structures, ideal angles are always ______ to their actual angles
About the same
Molecules can only be polar if…
If their chemical bonds are polar (& don’t cancel out)
Zeff charge is…
Z (atomic #) - (# of core electrons)
Cations are ___ than their neutral element, because _______
Cations are smaller than their neutral atom, because loss of an electron shrinks the atom
Ionization Energy
Energy required to completely remove an electron from its shell
Electronegativity
The tendency of an atom to attract electrons towards itself
Hydrophilic
Polar & Water loving
Hydrophobic
Non-polar & Water fearing
Kinetic Energy
The energy of an object in motion
Higher temp = higher kinetic energy!
Smaller Molar mass = higher energy!
The boiling point is higher if the ___, ____, & ____ is higher
Polarity, Branching area, & molar mass is higher
The 2 things that affect Solubility are….
Polarity
I.M.F.s
“Like dissolves like!”
big molecules are usually polar
Kelvin to Celcius
K - 273.15 = C
1 Dalton = …
1 g/mol
1 mol = ….
6.02x10^23
Interconversion!
2g = (x)mol/(x)g = (x)mol
The more ____, the higher the boiling point!
The more electrons, the higher the boiling point!
London Dispersion
(Non-polar) Affects evert molecule - Negative & positive parts of molecules attract, instantaneous dipole moment)
Dipole-Dipole
(Polar) Two polar molecules, positive end of one electronegative arrow attracts to the negative end of another
Hydrogen Bonding
Hydrogen donors & acceptors interlinking molecules
Hydrogen Donors
Hydrogens, but only hydrogens bonded to O, N, or F
Hydrogen Acceptors
Any O, N, or F
Ion-Dipole
Attraction between a charge ion (cation or anion), and a molecule w/a dipole (m+nm) + (nm +nm with dipole)
Solubility
Depends on
1. Polarity
2. IMFs
“Like Dissolves Like!”
Scientific Notation!
<— positive exponent! (larger)
—–> negative exponent! (smaller)
Multiplying SI’s
- Rewrite the the problem to group the mantissas (1st number) and powers of 10
- Multiply the mantissas
- Multiply (add) the powers of 10
Dividing SI’s
- Rewrite the the problem to group the mantissas (1st number) and powers of 10
- Divide the mantissas
- Divide (subtract) the powers of 10
Interconversion!
- Find a conversion factor
- Use conversion factor to write a unit ratio
- Multiply the measurement!
single bonds:
double bonds:
triple bonds:
1 sigma
1 sigma + 1pi
1 sigma + 2 pi
the lower the orbital the…
better it is at screening electrons from the influence of the nucleus
sp3
4 sigma bonds
0 pi bonds
(4 electron groups)
sp2
3 sigma bonds
1 pi bonds
(3 electron groups)
sp
2 sigma bonds
2 pi bonds
(2 electron groups)
sp3-
3 sigma bonds
0 pi bonds
sp2+
3 sigma bonds
0 pi bonds
Solving for Reactant (What mass of A is consumed w/5g of B given)
- Balance chemical equation
- 5g/20g(given)–> .25mol
- .25 molB –> .25mol A
- .25mol A (given A) –> 3.75gA!
Calculate the molar mass by
finding the sum of the molar masses, multiplied by the number of atoms in that element!
Solving for reactant, from mols
- (mols produced)/(mols consumed)
- (mols produced)/(given) = answer!
Finding mol ratio
- (atoms of x)/(atoms of y)
- (given mol)(x/y) = x!
moles —> mass
(molar mass)(moles given)
Could half of ____ reactant react??
- Calculate how much product would be produced if half the initial amount of reactant reacted
- Calculate how much of the otherrr reactant will be consumed if half the initial reactant will be consumed
- Is it more or less than the given of the second reactant?
Calculate the limiting reactant
- Balance equation
- g–>mol of both products, using molar mass and given grams
- which is smaller?
*remember to double atomic mass if ex: Cl2
THEORETICAL YIELD!
- Balance equation
- Find limiting reactant
- lr(mols. of what we want/mols of lr)=x
- (x)(molar mass of element we want) =theoretical yield!
% yield
(actual yield)/(theoretical yield)x100%
Heat released/or absorbed
How many mols of NO2 react?
(grams given)/(molar mass NO2) = mol NO2
(△given)55.3/2mol NO2 (mol NO2)
2.0824(55.3/2) = 57.578!
exo (-): released
endo (+): absorbed
Calculating heat of reaction from bond energies
- CH4 + 2O2 —> CO2 + H2O
- Draw Lewis structures to find amount of bonds
- Break - Make = Answer!
(E)
(v)
(λ)
(h) Plancks Constant
(c) Speed of light
(E) Energy
(v) Frequency
(λ) Wavelength
(h) 6.626x10^-34
(c) 299792458
n:
l:
ml:
n: shape of orbital (principal quantum #)
l: type of orbital (The principal angular momentum quantum number)
ml: orientation of suborbital (Magnetic quantum number)
L0:
L1:
L2:
L0: Sphere
L1: Hourglass
L2: 4-Leaf Clover
sp3d
5 electron groups
sp3d2
6 electron groups
Calculating wavelength from KJ/MOL
Given/Avogadros # = ___x10^-19
|
___x10^-19/Plancks = ____x10^14
|
299792458/____x10^14
= 0.0000 –> 000.0nm
Calculating wavelength from KHZ
299792458/given kHz
980 kHz —> 9.8x10^5
= 0.0000… —> 000.0nm
Calculating Frequency
299792458/given wavelength
18.5 tHz —> 1.85x10^13
= 0.0000… —> 00.0um
Formula for wavelength
λ=c/v
Formula for frequency
c/λ
Electromagnetic Spectrum In order of DECREASING wavelength
Gamma Rays
X-rays
Ultraviolet
Visible (400-700)
Infrared
Microwave
Radio
As wavelength _____, frequency and energy _____
As wavelength decreases, frequency and energy increase!
Finding Wavelength Graphically
absorbed (upwards arrow)
emitted (downwards arrow)
higher state - lower state = energy of photon (ex: 200)
(Plancks)(299792458)/2.00x10^19
=0.00 —-> 000.0nm
Atomic Ionizeability
Energy needed to ionize an atom decreases as you go DOWN the pt
S:
P:
S: 1 boob
P: 2 boobs
On a graph, the highest probability contains the ______, and the lowest probability contains the _____
The highest probability contains the LEAST energy, and the lowest probability contains the MOST energy
Hybridization Chain
1s2, 2s2, 2p6, 3s2, 3p6, 4s2, 3d10, 4p6, 5s2, 4d10, 5p6, 6s2, 4f14, 5d10, 6p6, 7s2, 5f14, 6d10, 7p6!
