Final Review Flashcards
How would you describe the Bohr Model of the atom?
electrons orbit the nucleus in shells (planetary model) + energy levels
How did the quantam mechanical model improve on the Bohr model?
It says that electrons do not orbit the nucleus, but in other regions of space. We only know the probability of finding electrons in these spaces
Describe the most current theory of the atom’s structure
large nucleus that contains neutrons & protons. Electrons exist around the nucleus in clouds
How are protons and electrons related in a neutral atom? How are they related in a charged atom?
Neutral - equal
Charged - one is more than the other
What conclusion about the atom was made from Rutherford’s gold foil experiment?
atoms are mostly empty space with a dense, positive, small nucleus
Describe the change in movements when electrons become “excited”
They jump up energy levels farther from the nucleus & become very unstable. Energy is absorbed as electrons move to higher energy levels
What causes color bands to be emitted?
As electrons become relaxed, they fall back to ground state and release the energy they absorbed into light and heat
What is the total number of electrons in all s orbitals of a neutral atom of phosphorous
6
How many valence electrons are in 1s^2,2s^2,2p^6, 3s^2, 3p^6, 4s^2
2
What is the maximum number of electrons that can occupy the 2nd energy level
8
What shape best represents the p orbital?
peanut / dumbbell
What is the electron config for an atom of germanium at ground state
check 19 in packet
what is the electron config for potassium atom at ground state
check 20 in packet
Draw an orbital diagram for the s-block elements in the third period
check 21 in packet
What type of nuclear decay is
4
He
2
Alpha
What type of nuclear decay is
0
e
-1
beta
which nuclear process decreases the atomic number by 1
beta
which nuclear process decreases the atomic mass by 4
alpha
The half-life of phosphorous is 14.3 days. How many mg of a 20 mg sample will remain after 85.8 days
.3125
When 42 / 19 K undergoes radioactive decay, the result is 2 products, one of which is calcium - 42. What is the other product?
0
e
-1
How are 2 atoms that are isotopes of the same element different from one another?
Different #s of neutrons and mass #s
How does Ga become a +3 ion
it loses 3 e-
Describe how 2 atoms in a covalent bond are both attracted to and repelled by one another
shared e- are attracted, the lone pair repels
What are the 2 different ions present in the compound Li3N?
Li+ , N3-
Is Mg(NO3)2 best classified as ionic or molecular?
ionic
What two properties are typical of molecular compounds?
- gases or liquids at room temp
- atoms share electrons
Which part of the atom is most directly involved in chemical bonding
electrons
What is the benefit of using pure iron filings instead of a pure iron nail to conduct a chemical reaction involving iron
more surface area makes filings more reactive
List these four elements from smallest to largest atomic radii: Cl, P, Si, S
Cl, S, P, Si
What property of elements is used to calculate the degree of polarity of a covalent bond between 2 atoms?
Electronegativity
Which element on the periodic table has the highest electronegativity
F
What causes a solution to become saturated
The maximum amount of solute has dissolved
When a solute is added to a solvent, how will the boiling point, freezing point, and vapor pressure be changed?
Boiling point increases, freezing point decreases, vapor pressure decreases
Equal concentration solutions of sodium chloride, aluminum chloride, magnesium nitrate, and aluminum sulfate are prepared. Which solute would be expected to cause the greatest change in boiling point compared to the pure solvent?
Al2SO43, because it has the most particles
What are 3 ways to increase the solubility of most solid solutes?
Increase temperature, increase surface area, increase agitaiton
What lab technique is best to seperate a solid from a liquid to recover the liquid
filtration
What physical property of substances is used in distillation to separate a mixture of liquids
boiling point
What is the formula for molarity?
n / L
what is the molarity of a 0.5 L sample of a solution that contains 60g of sodium hydroxide
3
Describe how to identify a base vs an acid by looking at the chemical formula
Base has OH, acids have H
What will happen to NaOH when phenolphthalein is added?
pink
What will happen to HCl when phenolphthalein is added?
colorless
what will happen to NH3OH when phenolphthalein is added?
pink
what will happen to NaCl when phenolphthalein is added?
Clear, bc its a salt
Tell whether each substance is polar or non-polar:
Water
Ammonia
Methane
Water: P
Ammonia: P
Methane: NP
The intermolecular forces present in HSCH2CH2SH
dipole-dipole
dispersion
Which pairs represent liquid combinations that will mix homogeneously?
Octane (C8H18) & H2O
Acetic Acid (CH3COOH) & H2O
Octane & Carbon Tetrachloride
Pair 2 &3 - if a compound is only carbons and hydrogens, it’s non-polar!
Why would C8H18 be soluble in CCl4, but NaCl wouldn’t be soluble in CCl4?
C8H18 are both NP, water is polar
What is the molecular geometry of PI3?
trigonal pyramidal
Molecular geometry of water
bent
molecular geometry of CO2
linear
molecular geometry of ammonia (NH3)
trigonal pyramidal
molecular geometry of methane (CH4)
tetrahedral
Identify 2 characteristics of an exothermic reaction that differs from that of an endothermic reaction
Releases heat to surroundings, -delta H
Which changes in phase would be considered exothermic?
Freezing, condensation, deposition
Fundamental Units
- independent of other units
- meter, second, kg, candela, ampere, kelvin, mole
Derived Units
- pressure, density, volume, velocity, force, energy
- found by multiplying, dividing, etc fundamental units
Difference between physical & chemical properties
physical can be observed without performing a reaction, while chemical can be observed during or after a reaction
Which phase has the strongest IMFs?
solids
Which phase diffuses an immeasureable amount?
solid
Which phase diffuses easily but slowly
liquid
which phase has no IMFs?
gas
which phase has vibrations only of molecules?
solid
Which phase diffuses easily and quickly?
gases
Formula for density
m / v
A student found a sample of an unknown liquid in the lab station cabinet. After experimentation, he found that the substance had a density of 1.65 g/mL. Will it float in water?
An object that is less dense than water will float, so no. 1.65 g/mL > 0.999 g/mL
Formula for volume?
m / d
Scientific Notation of Kilo
1 x 10 ^3
Scientific Notation of Centi
1 x 10 ^-2
Scientific Notation for Milli
1 x 10^-3
Scientific Notation for Micro
1 x 10^-6
Scientific Notation for Nano
1 x 10 ^-9
Accuracy
the degree of closeness of measurements to the true or accepted value
Precision
the degree to which repeated measurements under changed conditions show the same result.
How much water would form if 59.7 g of H reacted with 140.4 g of O
200.1
Formula for kinetic energy
0.5 (m)(v)^2
C –> K
+273
K –> C
- 273
What happens to temperature during phase changes?
it stays constant
5 postulates of kinetic molecular theory
1) Gases are mostly empty space because the separation is more than the size of the molecules.
2) Collisions with the sides of the container are more frequent & less frequent with each other. Collisions are elastic.
3) Particles move in a straight direction & randomly
4) Particles attract & repel because they don’t have any sense of IMFs
5) the average kinetic energy of all particles in a sample is proportional to temp
Boyle’s Law
P1V1 = P2V2. Pressure and volume have an indirect relationship.
Charles’ Law
V1/T1 = V2/T2. Direct relationship.
Gay-Lussac’s Law
P1/T1 = P2/T2
Dalton’s Law of Partial Pressure
Ptot = Pa + Pb + Pc
Ideal Gas Law
P = nrt
What would be the density of oxygen gas at 70 C and 3 atm?
Use MM = drt / p
Aufbau Principle
Electrons are placed in orbitals of lowest energy 1st
Pauli Exclusion Principle
- orbitals can hold 2 e-
- no 2 #s can have the same quantam numbers
- arrows have to have opposite spins
Hund’s Rule
when filling a sublevel, one e- enters each orbital until it’s full, then they pair
Isoelectronic
Same # of electrons
Lanthinides
1st row of box under table
Actinides
2nd row of box under table
How do you find something’s degree of polarity?
Find the difference between electronegativities
