phyparlec Flashcards

1
Q

EXTENSIVE property

A

A property that depends on the amount of matter in a sample

mass
volume
length

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2
Q

INTENSIVE property

A

Property that does not depend on the amount of substance present.

  • color
  • temperature
  • pressure
  • density
  • viscosity
  • surface tension
  • specific gravity
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3
Q

ADDITIVE

A

depends on the amount or size of the substance in a molecule

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4
Q

CONSTITUTIVE

A

depends on the arrangement/structure within a molecule

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5
Q

COLLIGATIVE

A

depends on the number of SOLUTE or concentration in solution

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6
Q

conversion

A

1mmHg = 1Torr
1atm = 760mmHg
1atm = 14.7 psi
1atm = 29inHg

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7
Q

Boyle’s Law

A

the Pressure and Volume of a gas are INVERSELY PROPORTIONAL
at constant temperature

P1V1 = P2V2

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8
Q

Charle’s Law

A

the Volume of the gas is
DIRECTLY PROPORTIONAL to its Temperature at constant pressure

V1/T1 = V2/T2

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9
Q

Avogadro’s Law

A

equal Volume of gases at the same temperature and pressure , contain equal Number of molecule

V1/N1 = V2/N2

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10
Q

Gay Lussac’s Law

A

Pressure of gas is directly proportional to its absolute Temperature at constant volume

P1/T1 = P2/T2

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11
Q

Combined Gas Law

A

equation that relates pressure, volume, and temperature of gas

(P1V1)/T1 = (P2V2)/T2

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12
Q

Partial Pressure

A

the pressure exerted by a single component in a mixture of gases

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13
Q

Dalton’s Law

A

the total pressure of a gas mixture is equal to the sum of the partial pressures of each individual gas

P(total) = Pa + Pb + Pc

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14
Q

Raoult’s Law

A

the vapor pressure in a solution or mixture is equal or identical to the vapor pressure of the pure solvent multiplied by its mole fraction in the solution

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15
Q

Ideal Gas Behavior
Van Der Waals Equation

A

an equation that corrects the Ideal Gas Law for intermolecular forces and molecular volume

(P + n2a/V2)(V-nb) =nRT

a/V2 accounts for the internal pressure per mole

b accounts for incompressibility of molecules, that is excluded (4x the molecular volume)

non ideality is greater when the gas is compressed
pressure is high and temperature is low

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16
Q

Molar Heat of Fusion

A

The amount of heat required to convert a unit mass of a solid into a liquid at its melting point.

Heat lost or gained in the conversion involving solid and liquid by 1 mole of substance

  • S→L
    • heat is absorbed therefore, + Hfusion
  • L→S
    • heat is released therefore, - Hfusion
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17
Q

Molar Heat of Evaporation

A

The amount of heat required to convert one mole of a substance from liquid to gas at constant temperature

Heat required for the conversion involving liquid and gas by 1 mole of a substance

  • L→G
    • heat is absorbed therefore, + Hvap
  • G→L
    • heat is released therefore, - Hvap
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18
Q

Gibb’s Phase Rule

A

determines the relationship for the least number of intensive variables that can be changed without changing the equilibrium state of the system

A principle that relates the number of phases in a system to the number of components and degrees of freedom, expressed as F = C - P + 2.

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19
Q

Phase

A

A homogenous part of the system, physically separated by distinct boundaries

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20
Q

Independent Variables

A

do not depend on the amount of matter present in the phases

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21
Q

Degrees of Freedom

A

the number of independent parameters that defines its configuration

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22
Q

critical pressure

A

pressure needed to liquify gas
also the highest vapor pressure that the liquid can have

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23
Q

critical temperature

A

temperature beyond which the liquid no longer exists

The further a gas is cooled below its critical temperature, the less
pressure is required to liquefy it.

For water, critical temp is 647K and pressure is 218 atm.

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24
Q

Eutectic Point

A

The temperature and composition at which two or more phases coexist in equilibrium.

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25
Q

Phase Diagrams are valuable for

A
  • interpreting interactions between two or more components
  • purity
  • melting point depression (determination)
  • possible liquification at room temperature
  • formation of solid solutions
  • formation of coprecipitates and other solid state interactions
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26
Q

KINETIC MOLECULAR THEORY OF GASES

A

Gasses are composed of particles called atoms or molecules, the total volume of which is so small as to be NEGLIGIBLE in relation to the volume of space in which the molecules are confined.
Gasses do not attract one another, but instead move with complete INDEPENDENCE.
- The particles exhibit continuous RANDOM MOTION owing to their kinetic energy. The average kinetic energy is directly proportional to the absolute temperature of the gas.
- E= 3/2RT
Gas molecules exhibit PERFECT ELASTICITY; that there is no net loss of speed or transfer of energy after they collide with one another and with the molecules in the walls of the confining vessel, which latter effect accounts for gas pressure.

  • High Temperature, High Kinetic Energy
  • Low pressure, Low Kinetic Energy
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27
Q

Diffusion

A

Process by which gas particles spread out in response to a concentration gradient.

  • Influenced by root mean square velocity
  • Lighter particles diffuse faster than heavier ones
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28
Q

Effusion

A
  • Process by which gas particles escape from a container into a vacuum through small hole.
  • Also related to root mean square velocity
  • Lighter particles effuse faster than heavier ones
29
Q

Graham’s Law of Effusion

A

the rate of diffusion or of effusion of a gas is inversely proportional to the square root of its molecular weight.

30
Q

basic gas law
density

A

density = PMW/RT
MW = wtRT/PV

31
Q
  • Liquefaction of gases
A
  • Low temperature
  • Also affected by pressure (high pressure)
  • If the temperature is elevated sufficiently, a value is reached above
    which it is impossible to liquefy a gas irrespective of the pressure applied.
32
Q

equilibrium vapor pressure

A

the pressure of the saturated vapor above the liquid

33
Q

Clausius-Clapeyron Equation

A

states that the logarithm of the vapor pressure of a substance is directly proportional to its reciprocal absolute temperature.
According to it, the natural logarithm of the liquid’s vapor pressure (P) is determined by the molar enthalpy of vaporization of the liquid (ΔHvap), the ideal gas constant (R), and the temperature (T) of the system.

34
Q

boiling point

A

The temperature at which the vapor pressure of the liquid equals the external or atmospheric pressure

All the absorbed heat is used to change the liquid to vapor, the temperature does not rise until the liquid is completely vaporized

The temperature at which agitation can overcome the attractive forces between the molecules of a liquid

35
Q

FM Raoult

A

found that a dissolved solute lowers the vapor pressure of the solvent.

36
Q

Vapor Pressure Lowering

A

The lowering of the vapor pressure of the solution to the vapor pressure of the pure solvent is proportional to the
number of molecules of solute in the solution.

the presence of non volatile solute particles in a liquid solution results in a reduction of the vapor pressure above the liquid

37
Q

Crystalline solids:

A

the particles are arranged in a 3 dimensional order.
The particles have equal intermolecular forces.
They have sharp melting point and are anisotropic.
They are called true solids.
Example: Benzoic acid, Diamond.

38
Q

Amorphous solids

A

Supercooled liquids in which the molecules are arranged in a somewhat random manner as in the liquid state.
* Glass, pitch, synthetic plastics are amorphous solids
* Tend to flow depending on pressure
* Do not have definite melting points

39
Q

Polymorphism

A
  • Substances that exist in more than one crystalline from, and are said to
    be allotropic.
  • Different stabilities and may spontaneously convert from the metastable form at a temperature to the stable form.
  • Exhibits different melting points, x-ray crystal and diffraction patterns,
    solubilities, even though they are chemically identical.
40
Q

Enantiotropic

A

change from one form to another is reversible.

41
Q

Monotropic

A

when transition takes place in one direction only
(metastable to stable)

42
Q

Isotropic

A

exhibit similar properties in all directions

43
Q

Anisotropic

A

– shows different characteristics in various directions along the crystal

44
Q

Cocoa butter

A
  • α – 22° C
  • β – 34.5° C – most stable, should not be heated until 35°C (up to 33° only);
    otherwise it will be destroyed.
  • β’ – 28° C
  • λ – 18° C
45
Q

Le Chatelier’s Principle

A

The principle which states that if a system at equilibrium is disturbed by a change in concentration, pressure, or temperature, the system will shift its equilibrium position so as to counter the effect of the disturbance

46
Q

Primary “stressors”

A
  • Changes in concentration
  • Changes in temperature
  • Changes in pressure
47
Q

Effect of Changes in Pressure or Volume on Equilibrium

A
  1. Add or remove a gaseous reactant or product. The effect of these
    actions on the equilibrium condition is simply that caused by adding or
    removing a reaction component, as described previously.
  2. Add an inert gas to the constant-volume reaction mixture. This has the
    effect of increasing the total pressure, but the partial pressures of the
    reacting species are all unchanged. An inert gas added to a constant-volume equilibrium mixture has no effect on the equilibrium condition.
  3. Change the pressure by changing the volume of the system. Decreasing
    the volume of the system increases the pressure, and increasing the system volume decreases the pressure. Thus, the effect of this type of pressure change is simply that of a volume change.
48
Q

Effect of Temperature on Equilibrium

A

The direction of the shift largely depends on whether the reaction is exothermic or endothermic.

  • Raising the temperature of an equilibrium mixture shifts the equilibrium condition in the direction of the endothermic reaction.
  • Lowering the temperature causes a shift in the direction of the exothermic reaction.

Per Le Chatelier’s principle, if the temperature is increased, a shift away from the side of the equation with “heat” occurs.
If the temperature is decreased, a shift towards the side of the equation with “heat” occurs.

49
Q

Effect of a Catalyst on Equilibrium

A

Adding a catalyst to a reaction mixture speeds up both the forward and reverse reactions. Equilibrium is achieved more rapidly, but the equilibrium amounts are unchanged by the catalyst.

50
Q

The Liquid Crystalline State

A
  • Liquid crystals aka mesophase, plasma
  • Part solid, part liquid
  • Dependent on temperature or pressure
51
Q

nematic phase

A

the molecules are not layered but
are pointed in the same direction.
As a result, the molecules are free to rotate
or slide past one another

52
Q

smectic phase

A

the molecules maintain the general order of the nematic phase but are also aligned in layers.

53
Q

cholesteric phase

A

the molecules are directionally oriented and stacked in a helical pattern, with each layer rotated at a slight angle to the ones above and below it

54
Q

formed using solvents

A

Lyotropic

55
Q

SOLUBILITY

A

Concentration of a solute when the solvent has dissolved all the solute that it can at a given temperature
*are homogeneous mixtures of two or more pure substances.
*the solute is dispersed uniformly
throughout the solvent.
*The intermolecular forces
between solute and solvent particles must be strong enough to compete with those between solute particles
and those between solvent particles.
*As a solution forms, the solvent pulls solute particles apart and surrounds, or solvates, them.
*If an ionic salt is soluble in water, it is because the ion-dipole interactions are strong enough to overcome the
lattice energy of the salt crystal.
*SOLUTIONS
* Simply put, three processes affect the energetics of solution:
* separation of solute particles,
* separation of solvent particles,
* new interactions between solute and solvent.

56
Q

SOLUBILITY
QUANTITATIVELY

A

Concentration of solute in a saturated solution at a
certain temperature

57
Q

SOLUBILITY
QUALITATIVELY

A

Spontaneous interaction of two or more substances to form a homogenous molecular dispersion

58
Q

SATURATED SOLUTION

A

the solvent holds as much solute as is
possible at that temperature.

  • Dissolved solute is in dynamic equilibrium with solid solute particles.
59
Q

UNSATURATED

A

less solute that can dissolve in the
solvent at temperature that is
dissolved in the solvent.

60
Q

supersaturated solutions

A

the solvent holds more solute than is normally possible at that temperature.
* These solutions are unstable; crystallization can usually be stimulated by adding a “seed crystal” or scratching the side
of the flask.

61
Q

equivalent weight

A

molecular weight divided by 𝑛𝑜. 𝑟𝑒𝑝𝑙𝑎𝑐𝑒𝑎𝑏𝑙𝑒 𝐻+ or H−

Acid/Base EW
HCl MW/1
HNO3 MW/1
H2SO4 MW/2
H3PO4 MW/3

62
Q

Very soluble

A

<1

63
Q

Freely soluble

A

1-10

64
Q

Soluble

A

10-30

65
Q

Sparingly soluble

A

30-100

66
Q

Slightly soluble

A

100-1000

67
Q

Very slightly soluble

A

1000-10,000

68
Q

Practically insoluble

A

> 10,000