Class notes
General Chemistry Final Exam Study Guide
- Course
- CHEM 1601
- Institution
- Vanderbilt University
Here is a comprehensive final exam study guide for the first semester of general chemistry. This will come in very handy!
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CHEM 1601Vanderbilt University
Final Exam Study Guide
Chapter 1 - Foundational Knowledge
● Law of conservation of mass = total mass of substances present after a chemical
reaction is the same as the total mass before. Matter is neither created nor
destroyed in a chemical reaction.
● Democritus said that matter is composed of small, indivisible particles called
atoms.
● Law of definite proportions = all samples of a given compound have the same
proportions by mass of their constituent elements.
● Law of multiple proportions = when two elements form two different compounds,
the masses of element B that combine with element A can be expressed as a
ratio of whole numbers.
● Dalton’s Atomic Theory:
1. Each chemical element is composed of indivisible particles called atoms.
2. All atoms of a given element have the same mass and other properties,
and are different from atoms of all other elements.
3. Different atoms combine in simple, numeric ratios to form compounds.
4. Atoms of one element cannot change into those of another element.
● In a chemical reaction, atoms only change the way they are bound together with
other atoms.
● J.J. Thomson used the cathode ray experiment to conclude that cathode rays are
negatively charged, lightweight particles of matter (electrons).
● Millikan’s oil drop experiment: he created an electric field between two metal
plates to measure the strength of the field (free fall/drop of an electron between
plates). Found that the charge on any drop was -1.60*10-19 C, the charge of a
single electron.
● Thomson invented the plum pudding model, where electrons floated in clouds
around the nucleus.
● Rutherford identified alpha (He2+) and beta (e-) radiation.
● In his gold foil experiment, most alpha particles passed straight through the gold
foil, but some were deflected and bounced back.
● Rutherford’s nuclear atom:
1. Most of the mass and all the positive charge of an atom is centered in the
nucleus. The nucleus contains most of the mass, but very little volume.
2. Most of the volume of an atom is empty space, where tiny, negatively
charged atoms are dispersed.
, 3. There are as many electrons outside the nucleus as there are positive
charges inside, so the atom is electrically neutral.
● James Chadwick discovered the neutron. The neutron has a similar mass to a
proton and accounts for mass, but has no charge.
● 1 amu = 1/12 the mass of a carbon-12 atom at rest.
● Changing the number of electrons turns an atom into an ion. Positive when
there’s fewer electrons than protons, negative when vice versa.
● Isotopes = atoms with the same atomic number but different mass numbers.
● Atomic mass = weighted average of all the isotopes of a given element in amu. A
single atom can only have the weight of an isotope, NOT the average.
● Atomic mass = sum of the (fractions*mass)
● 1 mole = 6.022*1023 particles
● Nuclear fusion = nuclei combine to form a larger one; gives off enormous energy.
Chapter 2 - Quantum Mechanics, Atomic Orbitals
● Wave-particle duality = light has properties of a wave, yet some as a particle.
● Light is electromagnetic radiation, energy embodied in oscillating, mutually
perpendicular electric and magnetic fields. Moves at 3*10^8 m/s in a vacuum.
● f = c/𝝀
● Frequency = number of peaks that pass by a stationary point in a given time
interval. Unit is cycles/s or Hertz.
● Speed = distance one peak will travel in a time interval.
● Frequency and energy are directly proportional, while wavelength is inversely
proportional to both.
●
● Constructive interference = two waves in phase combine to form a wave of larger
amplitude.
● Destructive interference = two waves out of phase cancel out and amplitude is
zero.
, ●
● Einstein's photoelectric effect:
○ Photoelectric effect = when light comes into a metal surface, it is released
as emitted electrons.
○ No electrons are emitted below threshold frequency, and the intensity of
light doesn’t have an effect.
○ Immediate electron ejection when light above threshold frequency hits
metal.
○ The higher the frequency (above threshold), the more KE the electrons
have.
○ The more intense the light is, the more electrons are ejected.
● E = hf = hc/𝝀, where E is energy and h is 6.626*10-34 J/s. Unit is joules/photon
● Photon = quantum = packet of light
● hv = binding energy of emitted photon
● KE (max KE of ejected electron) = Elight - binding energy. Because once
frequency exceeds the threshold frequency, the excess energy of a photon
transfers to an electron as kinetic energy.
● Binding energy = energy needed to remove an electron from a metal.
● When an atom absorbs energy (heat, light, or electricity), it re-emits it as light.
● Bohr model: orbits exist only at specific, fixed distances from the nucleus; energy
of each orbit is quantized as stationary states; radiation is emitted or absorbed
only when an electron makes a transition; the electron is never observed
between states, only in one state or another; no emissions occur while electrons
are in stationary states; electrons can only transition between stationary states.
● Electron interference is caused by SINGLE electrons interfering with themselves,
proving the wave nature of the electron is an inherent property of individual
electrons.
● De Broglie wavelength: 𝝀 = h/m(in kg)v = h/p
● Velocity of an electron is related to its wave nature, while position is related to
particle nature.
● Heisenberg’s uncertainty principle = we cannot simultaneously measure the
position and velocity of an electron with infinite precision.
● Equation: Δx * mΔv ≥ h/4π, v = uncertainty in velocity
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