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CHM 3001 Exam 1
Term | Definition |
---|---|
X-ray crystallography | the study of crystals and their structure by means of X-ray diffraction. |
Argonne National Lab | Advanced Photon |
Lawrence Berkley Lab | Advanced Light |
SLAC National Lab | Stanford Synchrotron Radiation Light |
Brookhaven National Lab | National Synchrotron Light 2 |
Ionic | ionic bonds |
Metallic | metallic bonds |
Covalent network | covalent bonds |
Molecular | dipole-dipole |
Crystalline solids | repeating pattern |
Amorphous | random |
Coordination number | the number of atoms, ions, or molecules that a central atom has (it's neighbors) |
Simple cubic coordination number | 6 |
Simple cubic atom density | 1 |
Body centered cubic coordination number | 8 |
Body centered cubic atom density | 2 |
Face centered cubic coordination number | 12 |
Face centered cubic atom density | 4 |
Lattice point | A point at the intersection of two or more grid lines (the center of the atom) |
Unit cell | the smallest group of atoms of a substance that has the overall symmetry of a crystal |
Lattice | a series of points that are arranged in a distinct pattern |
Cubic hole | the hole is at the center of simple cubic |
Octahedral hole | hole is at the center of an octahedron |
Tetrahedral hole | hole is at the center of a tetrahedron |
Solute | the substance that dissolves in a solvent to produce a homogeneous mixture. |
Solvent | a substance capable of dissolving or dispersing one or more other substances and providing a solution |
Solution | homogeneous mixture composed of two or more substances. |
Solubility | A degree to which a substance dissolves in a solvent to make a solution |
Golden rule of solubility | Like dissolves Like |
Electrolytes | substances that dissolve in water and produces ions and conduct electricity |
Nonelectrolytes | substances that dissolve in water but does not produce ions and can't conduct electricity |
Strong electrolytes | 100% of the dissolved substance generates ions |
Weak electrolytes | only a small fraction of the dissolved substance generates ions |
Ion dipole attraction | electrostatic attraction between an ion and a molecule with a dipole |
Solubility | the maximum concentration of a solute that can be achieved in a particular solvent under given conditions |
Solute's concentration = solubility | saturated |
Solute's concentration < solubility | unsaturated |
Solute's concentration > solubility | supersaturated |
Colligative properties | properties of a solution differ considerably from those of the pure solvent and pur solute |
Vapor pressure lowering | adding a nonvolatile solute to a pure solvent lowers the solvent's vapor pressure |
Chemical kinetics | the study of the rate of chemical reactions |
Average rate | rate of a reaction over a time period |
Instantaneous rate | rate of a reaction at a specific time |
Initial rate | rate of a reaction that started at 0 time |
Collision Theory | Reactants (atoms, molecules or ions) must collide in order to react with each other |
Transition state theory | The reactants form an intermediate called an activated complex called a transition state |
Reaction mechanism | a set of elementary steps that describe how a reaction occurs at the molecular level |
Elementary step | molecular-level view of a single process taking place in a chemical reaction |
Intermediate | a species produced in one elementary step and consumed in a subsequent step |
Catalyst | a substance that increases the rate of a chemical reaction by lowering the activation energy without itself being consumed by the reaction |
​​Homogeneous catalyst | is in the same phase as the reactants and speeds up the reaction by forming a reactive intermediate |
Heterogeneous catalyst | chemical catalysts whose physical phase is different from the physical phase of the reactants |
Enzymes | a biological catalyst and is almost always a protein. It speeds up the rate of a specific chemical reaction |
Electrolytes | chemical that can dissolve in water and generate ions |
Chemical Equilibrium | a reversible reaction that goes both forward and reverse directions, with equal rates, the concentrations of the products and reactants remain constant overtime |
Homogeneous equilibrium | reactants and products are present in the same phase |
When there is a constant concentration | Kc' or Qc' |
Heterogeneous Equilibrium | reactants and products are present in different phases |
Le chatelier's principle | When a chemical system at equilibrium is disturbed it returns to equilibrium by counteracting the disturbance |
If disturbed by adding a reactant or product the system will | proceed in the direction that consumes part of the added species |
If disturbed by removing a reactant or product the system will | proceed in the direction that restores part of the removed species |
At equilibrium | Q=K |
Rate Law 1st order | rate = k[A] |
Units of rate constant 1st order | s^-1 |
Half-Life 1st order | t1/2 = 0.693/k |