| Term |
Description |
| colligative properties |
Vapor-pressure depression (boiling-point elevation), freezing-point depression, osmotic pressure. |
| solubility |
The amount of solute that will saturate a particular solvent. |
| molality |
Moles of solute per kilogram of solvent |
| mole fraction |
Moles of solute over total moles of solution |
| Solutes dissolve best in solvents... |
... where the intermolecular forces being broken in the solute are being replaced by equal or stronger forces between the solvent and the solute. |
| Molality is useful because... |
... it is independent of temperature and pressure. |
| strong electrolytes |
Ionic substances that dissociate completely |
| weak electrolytes |
Ionic compounds that do not dissociate completely |
| Strong electrolytes... |
...conduct electricity better than weak electrolytes. |
| van't Hoff factor |
("i") The number of ions a unit of a substance will produce in a given solution. (Ex: For NaCl, i = 2) |
| ionizability |
("i") See van't Hoff factor. |
| All ionic compounds... |
... are strong electrolytes, whether soluble or not. |
| Solubility of salts in water (1) |
All Group I (Li, Na, K, Rb, Cs) and ammonium salts are soluble. |
| Solubility of salts in water (2) |
All nitrate (NO3-), perclorate (ClO4-), and acetate (C2H3O2-) salts are soluble. |
| Solubility of salts in water (3) |
All silver, lead, and mercury salts are insoluble (except for compounds soluble under rule 2). |
| Phase solubility (1) |
The solubility of solids in liquids tends to increase with increasing temperature. |
| Phase solubility (2) |
The solubility of gases in liquids tends to decrease with increasing temperature. |
| Phase solubility (3) |
The solubility of gases in liquids tends to increase with increasing pressure. |
| Colligative properties... |
are only dependent on the number of particles in the solution, and are independent of the identity of particle. |
| vapor pressure |
The pressure exerted by the gaseous phase of a liquid that evaporated from the exposed surface of the liquid. |
| volatile |
Having high vapor pressure. |
| boiling point |
The temperature at which the vapor pressure of a solution is equal to atmospheric pressure. |
| Salt water... |
... has a lower vapor pressure and boils at a higher temperature than pure water. |
| Raoult's Law |
The partial vapor pressure of a particular substituent in a solution is proportional to its mole fraction. |
| Dalton's Law |
The total vapor pressure over a solution is the sum of the partial vapor pressures of the substituent liquids. |
| vapor-pressure depression |
Change in partial pressure of a solution due to dissolution of nonvolatile solute B into solvent A is equal to the negative product of the mole fraction of B and the partial pressure of pure A. |
| ideal solution |
A solution where all intermolecular forces are equal. |
| Vapor-pressure depression occurs because... |
... dissolution of a solute in a solvent closes the entropy gap between the soution and vapor phases. The smaller increase in entropy from evaporation leads to less tendency to evaporate. Occurs only in solid-liquid solutions. |
| Boiling point elevation occurs because... |
... when vapor pressure is depressed, higher temperature is needed to vaporize the solution. Occurs in only solid-liquid solutions. |
| The behavior of a liquid-liquid solution deviates from Raoult's Law when... |
... (1) Intermolecular forces between the liquids are weaker (resulting in higher vapor pressure); (2) Intermolecular forces are stronger (resulting in lower vapor pressure). |
| boiling-point elevation |
= (k)(i)(m); k = solvent's boiling point elevation constant, i = solute's van't Hoff factor, m = molality of the solution |
| Freezing-point depression occurs because... |
... soluting a solvent increases the entropic difference between the solution and solid phases (making things easier to melt and harder to freeze). Occurs in both solid-liquid and liquid-liquid solutions. |
| freezing-point depression |
= -(k)(i)(m) |
| osmotic pressure |
= iMRT |
| force exerted by a spring |
F = -kx |
| elastic potential energy |
E = (1/2)kx^2 |
| frequency of a block oscillating on a spring |
f = (1/2pi)sqrt(k/m) |
| period of a block oscillating on a spring |
T = 1/f |
| A pendulum undergoes... |
... not simple harmonic motion. When the angle is small, though, it acts like a simple harmonic. |
| frequency of an oscillating pendulum |
f = (1/2pi)sqrt(g/L). (Note: only applies to small angles.) |
| wave speed |
= (wavelength)(frequency) |
| wave speed on a rope |
= sqrt(T/D); T = tension, D = linear density |
| Wave speed depends on... |
... the type of wave and the characteristics of the medium, and not the frequency. Light through a material medium is the only exception. |
| When a wave passes into a different medium... |
... speed changes, but not frequency. |
| The amplitude of a wave depends on... |
... energy, not frequency, wavelength, or wave speed. |
| fundamental |
The first harmonic, whose wavelength is double the length of the rope |
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