Chemistry Liquids and Solids Flashcards
Because of their smaller volume relative to ___, liquids and solids are also referred to as condensed phases
gases
Gases are easily compressed to ___ volume
smaller
The movement of a ___ can be defined as viscosity. Viscosity is a measure of a fluid’s resistance to flow
liquid
In other words, ___ describes the internal friction of a moving fluid
viscosity
The degree to which two ___ can mix is called their miscibility
liquids
Under extreme conditions, such as violent shaking, two immiscible __ can form a fairly homogenous mixture called on emulsion
liquids
The particles’ only motion is ___ about fixed positions, and the kinetic energy of solids is predominantly vibrational energy
vibration
A crystalline solid, such as NaCl, possesses an ordered structure; its atoms exist in a specific, three-dimensional ___ with repeating patterns of atoms, ions, or molecules
geometric arrangement
An amorphous ___, such as glass, has no ordered three-dimensional arrangement, although the molecules are also fixed in place
solid
___ are aggregates of positively and negatively charged ions; there are no discrete molecules
ionic slids
The physical properties of ___ include high melting points, high boiling points, and poor electrical conductivity in the solid phase
ionic solids
Crystals both ionic and metallic) are defined by their ___, which represent the smallest repeating units that compose the larger crystalline structure
unit cells
The ___ are the most important; simple cubic, body-centered cubic, and face-centered cubic
cubic cells
The heat Q gained or lost by a substance when the ___ of that substance is changed by T is given by:
Q = mcdeltaT=mc(T sub f - T sub i)
where m is the mass of the object and c is a constant called the specific heat
temperature
The ___ is defined as the amount of heat required to raise a unit mass of a substance 1 K or 1 degree Celsius and depends solely on the material of the object
specific heat
The total amount of heat gained or lost by a ___ during a phase change is given by:
Q = mH sub L
where Q is the heat gained or lost, m is the mass of the substance, and H sub L is the latent heat of transformation of the substance
substance
The ___ from liquid to solid, or solid to liquid, occurs at the melting-point temperature
phase change
The corresponding heat of ___ (during a phase change) is often referred to as the heat of fusion and is written as delta H sub f. On the other hand, the phase change from liquid to gas, or gas to liquid, occurs at the boiling-point temperature. here the heat of transformation is often referred to as the heat of vaporization and is written as delta H sub v
transformation
Each time the liquid loses a high-energy particle, the ___ of the remaining liquid decreases; thus, evaporation is a cooling process
temperature
If a cover is placed on a beaker of liquid, the escaping ___ are trapped above the solution. These molecules exert a countering pressure, which forces some of the gas back into the liquid phase; this process is called condensation
molecules
___ increases as temperature increase, since more molecules have sufficient kinetic energy to escape into the gas phase
vapor pressure
The ___ at which the vapor pressure of the liquid equals the external pressure is called the boiling point
temperature
Whereas pure crystals have distinct melting points, amorphous solids, such as glass, tend to melt over a larger ___ of temperatures due to their less-ordered molecular distribution
range
The reverse (of ___) transition, from the gaseous to the solid phase, is called deposition
sublimation
For an equilibrium between a ___ and a solid:
delta G = G (g) - G (s) so G (g) = G (s) at equilibrium
gas
A standard ___ depicts the phases and phase equilibria of a substance at defined temperatures and pressures
phase diagram
At the ___, unique for a given substance, all three phases are in equilibrium
triple point
The point at B is known as the critical point, the temperature and pressure above which the liquid and gas phases are not possible and ___ fluids exist instead
supercritical
Raoult’s law enables one to determine the relationship between the vapor pressure of vapor A and the ___ of liquid A in the solution
concentration
When solute B is added to pure ___ A, the vapor pressure of A above the solvent decreases. If the vapor pressure of A above pure solvent A is designated by P degree sub A and the vapor pressure of A above the solution containing B is P sub A, the vapor pressure decreases as follows:
delta P = P degree sub A - P sub A
This pressure decrease is also equivalent to:
delta P = X sub B P degree sub
where X sub B is the mole fraction of the solute B in solvent A (mol B/ total moles).
Because X sub B = 1 - X sub A and delta P = P degree sub A - P sub A, substitution into the above equation leads to the common form of Raoult’s law:
P sub A = X sub A P degree sub A
Similarly, the expression for the vapor pressure of the solute in solution (assuming it is volatile) is given by:
P sub B = X sub B P degree sub B
solvent
Raoult’s law holds only when the attraction between molecules of different components of the mixture is equal to the attraction between the molecules of any one ___ in its pure state
component
Solutions that obey Raoult’s law are called ___ solutions
ideal
___ are physical properties derived solely from the number of particles present, not the nature of those particles. These properties are usually associated with dilute solutions
colligative properties
___ (H20) freezes at 0 degrees Celsius; however, for every mol of solute particles dissolved in 1L of water, the freezing point is lowered by 1.86 degrees Celsius
pure water
The formula for ___ the freezing-point depression (due to solutes in pure solvent) is:
delta T sub f = iK sub f m
where delta T sub f is the freezing point depression, K sub f is a proportionality constant characteristic of a particular solvent, m is the molality of the solution (mol solute/ kg solvent), and i is the van’t Hoff facto, which accounts for the number of particles that dissociate from the original molecule
calculating
A liquid boils when its vapor pressure equals the atmospheric pressure. IF the ___ of a solution is lower than that of the pure solvent, more energy (and consequently a higher temperature) will be required before its vapor pressure equals atmospheric pressure. The extent to which the boiling point of a solution is raised relative to that of the pure solvent is given by the following formula:
delta T sub b = i K sub b m
where delta T sub b is the boiling point elevation, K sub b is a proportionality constant characteristic of a particular solvent, m is the molality of the solution an di is the van’t Hoff factor
vapor pressure
Consider a container separated into two compartments by a ___. One compartment contains pure water, while the other contains water with dissolve solute. The pressure exerted by the water level in the solute-containing compartment due to gravity will eventually oppose the influx of water due to diffusion (from the pure solvent container to the one with solute), and the water will stop flowing once this point is reached. This pressure is defined as the osmotic pressure (upper case pi) of the solution san dis given by the formula:
upper case pi = iMRT
where M is the molarity of the solution, R is the ideal gas constant, T is the temperature on the kelvin scale, and i is the van’t Hoff factor
This equation shows that molarity and osmotic pressure are directly proportional (i.e., as the concentration of the solution increases, the osmotic pressure also increases). Thus, the osmotic pressure depends only on the amount of solute, not its identity
semipermeable membrane
