CHEM 1A Study Guide - Final Guide: Pauli Exclusion Principle, Black-Body Radiation, Absorption Spectroscopy
CHEM 1A
8/23/17
I. Atoms, Molecules, and Stoichiometry
A. Stoichiometry: relationships between quantities of matter that participate in chemical
reactions
1. Reactants —> Products
2. Less stable —> More stable
a) Energy is lower
b) Breaking bonds absorb energy/ Forming bonds release energy
3. Always an integer relationship
4. Reactions need activation energy to occur
a) Some need catalysts
5. Transition state
a) Stabilizes the components
(A mixture of hydrogen and oxygen will make the biggest boom)
-Pure hydrogen is slow, needs to find oxygen
-Mixture makes biggest boom because the molecules are closer to each other
-Oxygen is anticlimactic because it doesn't have any hydrogen
B. In some reactions, the reaction will constantly shift from products to reactants
C. Macroscopic (bulk) VS Microscopic (atomic, molecular) level
1. Avogadro’s Constant: 6.02 x 10^23 = number of atoms in one mole of C(12)
2. Molar Mass (g/mol)
3. Mass is always conserved (Law of Conservation of Mass)
II. Atomic structure
A. Top: Mass number; Bottom: Atomic number
1. Mass number= Protons + Neutrons
2. Isotopes: same element, different number of neutrons
B. Mass spectrometer
1. Sample —> heating and ionization —> accelerator —> magnetic field
a) Small molecules have greater deflection
2. Figures out mass of individual masses of the components of a sample
3. Height —> indicates relative amount of substance
C. Empirical formula: lowest integer value ratio of elements in a molecule
D. Molecular formula: actual integer value
III. Light as a Wave
A. lambda*v= speed of light
1. C: speed of light 3.0x10^8 m/s
2. Lambda: wavelength
3. v: frequency
B. Electromagnetic spectrum: y- rays —> x- rays —> UV —> IR —> MW —> Radio
C. Absolute thresholds of perception: A candle on a dark clear night at 30 miles
D. Diffraction
1. shoot light through a slit and the light will split and spread
2. The longer the wavelength, the more it will bend
E. Interference
1. Constructive
a) Peak lines up with peak
2. Destructive
Document Summary
Pure hydrogen is slow, needs to nd oxygen. Mixture makes biggest boom because the molecules are closer to each other. Oxygen is anticlimactic because it doesn"t have any hydrogen. In some reactions, the reaction will constantly shift from products to reactants. B: macroscopic (bulk) vs microscopic (atomic, molecular) level, avogadro"s constant: 6. 02 x 10^23 = number of atoms in one mole of c(12, molar mass (g/mol, mass is always conserved (law of conservation of mass) Atomic structure: top: mass number; bottom: atomic number, mass number= protons + neutrons. E: peak lines up with peak, destructive, nodes: dark spots > zero probability of nding light, absorption and emission, continuous: a single molecule absorbs very speci c wavelengths. B. trident^2: probability of nding an e- three quantum numbers: n, l, m: n: principal. The photoelectric effect illustrates the particle nature of light. Light wave/particle duality: momentum=mass*velocity (a light particle can have momentum): p=mv, e=mc^2=pc.
