Chemistry

The volume of gas is affected by a change in what two things?
pressure and temperature
Gases have relatively low ________ and low ______.
density/viscosity
G

Gases are miscible.

What does this mean?

That they mxi easily with other gases.

What are the four units of pressure?

And how are they all related?

atmospheres; torr; mmHg; Pascals

 

1 atm=760 torr=760 mmHg=1.01E5 Pa

What is included in the ideal gas equation

PV=nRT

pressure (atm)

volume (L)

number of moles

R (constant) .08206 atm-L/mol-K

What are the rules for R as a constant as far as when to use it and what are each of the values?

R for pressure (atm/torr) .08206 atm-L/mol-K

 

R for energy (heat/energy) 8.314

What is Boyle’s law?

V1P1=V2P2

;

volume and pressure are indirectly proportional

What is shown in Charle’s Law?
volume is proportional to temperature
What does Avogadro’s Law state?
that volume is proportional to the number of moles

What does STP stand for?

what what are the values?

standard temperature and pressure

;

T= 0 degrees celsius

273.15 K

;

P= 1 atm

;

standard molar volume: 22.4 L

What is the definition of standard molar volume?

one mole of any gas will occupy 22.4 L at STP.

;

(depends on number of moles… it may double or triple)

State the law of partial pressures:
for a mixture of non-reacting gases, the total pressure is the sum of the partial (of individual) pressures for each gas
what theory allows us to derive certain equations regarding the motion of indivudal gas particles?
kinetic-molecular theory, KMT
KMT looks at the _________ in energy of the gas molecules
changes
Increasing temperature casues an increase in ________?
energy
What causes the average velocity and the collisions to increase?
increasing temperature
In the kinetic energy equation, which R is used?
R= 8.314 J/mol-K
the process in which a gas escapes (of leaks) from its container through a small hole
effusion
what is the law of effusion for an ideal gas?
the rate of effusion of a gas is inversely proportional to the square root of its molar mass
The rate of effusion compares what?
what rates of effusion between two different gases, A and B
Can the rate of effusion equation be replaced to solve for time?
most definitely
What is the motion of one gas moving through another gas?
diffusion

at a given temperature, the energy and the speed of a molecule is inversely proportion to what?

;

(rate of effusion equation)

mass
What value for R is used in the root-mean-square equation?
R= 8.314 J/mol-K

IDEAL GASES:

-work best as ____ pressure and ____ temperatures

-assumes no ________ ______

-assumes no ______ ______

low/high

intermolecular interaction

molecular volume

REAL GASES:

-molecules have _______ size and occupy ______

-molecules have _______ forces that become significant when they are in close proximity

-at ______ pressures attractive forces lead to the appearance of fewer ______

-at very _____ pressure the finite volume of molecules causes repulsion and leads to the appearance of more ____

finite/space

attractive

high/moles

high/moles

in the real gas equation:

;

pressure values are adjusted to account for…?

;

what is the constant?

;

attractive interactions of intermolecular forces

;

a

in the real gas equation:

;

volume is adjusted to account for the…?

;

what is the constant?

finite volume, molecular shape and the increased frequency of collisions

;

b

who proposed the real gas equation?
van der waals

what two components make up a majority of the earth’s atmosphere?

 

in what proportions (%volume and mole fraction)

nitrogen N2

78.084%

.78084

 

oxygen O2

20.948%

.20948

 

what does the pressure at a given altitude depend on?
thew eight of the gases above it

at a lower altitude the pressure is greater.

 

why?

because there is more gas above
pressure decreases and what increases?
altitude.
temperature in the atmosphere results from gas molecules ______ the sun’s high energy ______.
absorbing/radiation
the absorption causes molecules to ?
ionize
warming is caused by the _______ cycle.
ozone
ozone absorbs what kind of light?
ultraviolet light
in photodissociation, how much energy is required to break O2 bonds?
495 kJ/mol
the concentration of O2 ________ as altitude increases.
decreases

ozone:

– ___ resonance forms

– ____ stable than O2

-_____ bond length than O2

-Bent angle at ____degrees

-what color?

2

less

longer

117

light blue gas

what is the primary benefit of ozone?
it protects us from dangerous UV radiation

how many reactions are needed to form ozone?

;

how many reactions are needed to destroy ozone?

2

;

1

what destroys ozone?
CFCs
where do CFCs diffuse to?
the upper atmosphere
when CFCs undergo photodissociation, what is released?
chlorine atom
what has replaced CFCs?
HFCs
what is the lowest portion of earth’s atmospher?
troposphere
energy coming into the earth is mostly?
solar
what percentage of energy is reflected by the atmosphere?
30%
what type of energy is absorbed by the atmosphere?
UV
Most of the radiation hits earth’s surface and is absorbed. what does this cause?
warming
earth’s surface radiates ehat back into the atmosphere in the form of ________ heat.
infrared
what absorbs infrared heat?
H2O, CO2, CH4, O3
what gases in thermal regulation lead to the greenhouse affect?

carbon dioxide

 

water

what are the three states of matter?
solid, liquid, gas

Solid state:

-_________ force between the particles is far _____ than the ________ _____ of the particles.

attractive/greater/kinetic energy

solid state:

 

-particles remain in _______

-solid has a ______ shape

-no _______

-no _____ ___ _____

 

stronger IF’s mean…

-position

-specific

-compressibility

-ability to flow

;

higher melting point

Liquid state:

;

________ _____ of the particles is ______ than those in a solid but still weaker than the ______ ____

kinetic energy

stronger

attractive force

liquid state:

;

___ = ____

IF = KE

liquid state:

;

-kinetic energy allows for particles to ____ ____, but remain in virtual _____

-very low ______

-moderate ____ __ ____

tumble randomly/contact

compressibility

ability to flow

liquids with strong IF will have what?
higher boiling points

Gas State:

the _____ ____ of the particles is stronger than _____ _____

;

-occupy the shape of the _____

;

-high _______

-high _____ __ ____

kinetic energy

attractive forces

;

container

;

compressibility

ability to flow

solid —> liquid

 

endo or exo?

melting/fusion

 

endo

liquid —-> gas

 

endo or exo?

vaporization

 

endo

solid —> gas

 

endo or exo?lo

sublimation

 

endo

 

** at low pressure

gas —> liquid

 

endo or exo?

 

condensation

 

exo

liquid —> solid

 

endo or exo?

freezing

 

exo

gas —-> solid

 

endo or exo?

deposition

 

exo

what are the delta H symbols?

 

liquid and solid…

 

liquid and gas…

 

solid and gas…

fus

 

vap

 

sub

definition:

 

the amount of heat needed to change the temperature of 1 gram of a substance by 1 Kelvin

specific heat capacity
specific heat capacity is _____ for every compound in every ______/
unique/phase
what specific heat capacity is replaced by molar heat capacity, what are the units?
J/mol-K

Phase change:

 

during a phase shift, the ______ remains constant and all heat energy changes result from either _______ or ____ the _____ between the molecules within the substance

temperature

forming/breaking

bonds

in the phase change from a gas to liquid or liquid to solid: the energy is _______ as molecules _____ bonds.
released/form
during phase changes from solid to liquid or liquid to gas, the energy is ____ and molecules _____ bonds.
absorbed/break

energy changes are calculated using:

 

 

delta H: fusion

delta H: vaporization

what is the first law of thermodynamics?
energy cannot be destroyed or created, only transferred
the amount of heat lost by a system ____ the amount of heat gained by the surroundings
equal
what are the two most common types of calorimeters?

bomb calorimeters

 

coffee cup calorimeters

the rate of vaporization is greater than the rate of condensation. which causes for what to happen?
molecules break free from the surface of water and enter the gas phase
what will increase as more and more gaseous water molecules leave the surface?
pressure of the water vapor in the container
does the pressure eventually reach a maximum?
yes.
what causes for there to be a maximum in pressure?
the fact that the rate of vaporzation is now equal to the rate of condensation
when the rate of vaporization is now equal to the rate of condensation, what does this actually mean?
the same amount of water molecules are leaving the surface as there are joining the surface
a system is in equilibrium when…
the same amount of water molecules are leaving the surface as there are joining the surface
what happens when liquid’s vapor pressure reaches the external pressure (usually atmospheric pressure)?
it boils
the boiling point at atmospheric pressure, 1 atm?
normal boiling point
at higher altitudes, water will boil at a _____ temperature
lower
what causes for more molecules in a liquid to escape to the gas phase?
higher temperature
what two major factors affect vapor pressure?
temperature and intermolecular forces

temperature:

-raising the temperature increases the _____ ____ of the molecules, making it easier for them to escape from the ______, and harder for them to _______.

 

-in general, the higher the temperature, the higher the ______ _______

kinetic energy/surface/return

 

vapor pressure

intermolecular forces:

-these are the _____ ____ that keep particles ______. Weake intermolecular forces allow the particles to _______ more easily.

 

-in general, the weaker the intermolecular forces, the higher the ______ _____.

attractive forces/together/vaporize

 

vapor pressure

what two factors affect the phase of a substance?
pressure and temperature
what is the point at which all three phases are in equilibrium?
triple point
what is the point called where the liquid/gas line ends?
critical point
at the critical point, the liquid and vapor pressure are ______.
equal
beyond the critical temperature, what exists?
supercritical fluid

for normal compounds, an increase in pressure will result in the phase change of liquid to solid, like CO2.

 

Why is this?

because the solid is denser than the liquid
why is the line screwed up for H2O in the phase diagram?
because water is denser than ice
what is a solution?
a solute dissolved in a solvent

the maximum amount that can be dissolved into a fixed amount of a specific solvent at a given temperature.

 

what is this?

solubility of a solute
what are the six intermolecular forces?

1. ion-dipole (ion-polar)

2. dipole-dipole (two polar molecules)

3. hydrogen bonding (H-NOF)

4. ion-induced dipole (ion-nonpolar)

5. dipole-induced dipole (polar-nonpolar)

6. dispersion (London) (nonpolar-nonpolar)

intermolecular forces directly affect…
solubility

common solution:

 

_____ solvents

______ or ______ solutes

liquid

liquid/solid

what does “like dissolves like” mean?
substances with similar types of intermolecular forces are more likely to dissolve in each other

solubility:

 

-ions and polar molecules will readily dissolve into ______ solvents

 

-nonpolar molecules will readily dissolve into ______ solvents

polar

 

 nonpolar

when a solution is formed, energy is either ______ or ______.

 

which is measures by a change in ______.

released/absorbed

 

enthalpy

enthalpy

 

solute particles separate

solvent particles separate

solute and solvent mix

endo

endo

exo

what must be added together in order to find the enthalpy of the solution?
the enthalpy of the solute, solvent, and mix
what does it mean if the change in H is positive?
the process is endothermic and the solute won’t dissolve well in the solvent unless change in entropy is very high
What does it mean if change in H is negative?
the substances will readily dissolve

what is it called when solvent particles surround a solute particle?

 

what is this called in water?

solvation

 

hydration

when a solution is forming, solute particles break apart from one another and become dispersed in the solvent. but what can happen on occasion?
the solute particles collide with undissolved solute and recrystalize
rate of dissolving at first is faster than the rate of…
recrystalizing
when the rate of dissolving and the rate of recrystalizing occur, they will eventually even out which is called the
equilibium
if a solution contains the maximum amoutn of dissolved solute particles at a given temperature, it is considered…
saturated

what if it has less than the maximum amount of dissolved solute particles?

 

what if it has more?

unsaturated

 

supersaturated

temperature and solubility:

 

for solids, increasing temperature ______ solubility.

 

for gases dissolved in water, increasing temperature ______ solubility.

increases

 

decreases

pressure and solubility

 

-as pressure increases, the solubility of a gas _______

 

increases
what is the amount of solute present within a given volume of the solution?
concentration
how is molarity expressed?

M

 

moles of solute/Liters of solution

when diluting, what changes?
volume
what are 5 ways to express concentration: the proportion of a substance in a mixture?

1. molarity (M)

2. molality (m)

3. parts by mass

4. parts by volume

5. mole fraction (x)

what are concentrations measured in if they are very small amounts?
ppm and ppb
solutes that are cpaable of dissociating are often called…
electrolytes
strong electrolyate dissociate ______ in water and are _____ conductors of electricity.
completely/good
weak electrolyate only dissociate _____ and are _____ conductors.
partially/poor
nonelectrolyates do not _______ in water and are ________.
dissociate/non-conductors
if a water soluble comound is ionic, then it is definitely a…
strong electrolyte

not all electrolyates are ionic compounds…

 

true or false

 

true
ionic compounds are only good conductors if the compound is …
soluble
colligative properties are ________ properties.
physical
colligative properties depends on the _______ of solute particles dissolved in a given solvent.
number
the four types of colligative properties that can affect a solution are:

1. vapor pressure lowering

2. osmotic pressure changes

3. boiling point elevation

4. freezing point depression

lowering vapor pressure

 

-the vapor pressure of a solution is always ______ than that of the pure solvent

 

-what law proves this?

lower

 

Raoult’s Law

boiling point increase

 

a solution has a _______ boiling point than the pure solvent

higher

freezing point decrease

 

-a solution freezes at a ______ temperature than a pure solvent

lower

Van”t Hoff Factor, i

-refers to how the amount of ______ _____ can increase if the solute itself i able to ______ into its constituent ions.

-______ that are capable of _______ in solution are often called ________

 

solute particles/dissociate

 

solutes/dissociating/electrolytes

osmotic pressure

 

-known also as ______ pressure

-it is produced by a solution with a ________ in the concentration of solute

 

— Van’t Hoff factor refers to how the mount of solute particles ______ by a ________ factor if the solute is an ionic compound and _______ into its _________ ions.

hydrostatic

 

differential

 

increases/specific/dissociates/constituent

x

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