Ap Chem Ch. 10-11 Flashcards
Force(massXacceleration) acting on an object per unit area.
Pressure-
P=f/a
4 properties of gases:
- expand to fill their containers
- highly compressible
- always mix homogeneous with other gases
- only occupy a small fraction of the actual volume of their container
- extremely low densities
Weight of air per unit of area
Atmospheric pressure
Pascals-SI units
1 Pa= 1 N/m^2
Bar
1 bar= 10^5 Pa= 100 kPa
Difference in the heights measured in mm(h) of two connected columns of mercury
mm Hg , torr
Normal atmospheric pressure at sea level
Standard pressure
Convertions for standard pressure
1 atm = 760 torr = 760 mm Hg = 101.325 kPa
Volume is _________ proportional to Pressure.
Inversly
P1V2=P2V2
Voulme is ___________ proportional to temperature
Directly
The volume of a gas at constant temperature and pressure is _________ proportional to the number of moles of the gas.
Directly
Pressure is ________ proportional to kelvin temperature.
Directly
Charles’ law
V1 V2
➖ = ➖
T2 T2
Boyle’s law
P1V2=P2V2
Gay-lussac’ law
P1 P2
➖ = ➖
T2 T2
The product of the pressure and volume of a fixed quantity of gas is ______ proportional to the kelvin temperature.
Directly
Conbined gas law
P1V1 P2V2
➖➖ = ➖➖
T1 T2
Ideal gas law:
PV=nRT
Constants for R( ideal gas constant)
.08206 L(atm) / mol( k)
- 314 L(kPa) / mol(k)
- 36 L(mm Hg) / mol(k)
- 314 J / mol(k)
Solving for the volume of 1 MOL at standard temperature and pressure (STP) gives 22.41 L / mol
Standard molar volume
Molar mass form of ideal gas law
M= mRT
——
PV
Density form of the idal gas law
D= MP
—–
RT
In which cases would you know you have to use Gas stoichiometry ?
- they have to be at constant pressure and temperature
* look for an equation
The total pressure of a mixture of gases equals the sum of the pressures that each would exert if it were present alone.
Dalton’s law of partial pressures
P(total)= P1+P2+P3…
Gases consist of large numbers of molecules that are in continuous, random ______.
Motion
The speed of a molecule possessing AVERAGE KINETIC ENERGY.
Root-mean-square speed
The escape of gas molecules through a tiny hole into an evacuated space.
Effusion
The spread of one substance throughout a space or throughout a second substance.
Diffusion
Which diffuse faster, lighter molecules or heavier molecules??
Lighter molecules
Distance between collisions
Mean free path
Root-mean-square speed equation
______
u= | 3rT
—-
M
Properties of solids
- Definite shape and volume
- ordered arrangement
- fixed positions
- virtually incompressible
- Diffusion occurs extreamly slowly
- close together
Properties of liquids
- Definite volume, but takes shape of container
- disorder
- virtually incompressible
- Flows readily
- diffusion occurs slowly
- particles close together
The state a substance is in at a particular temperature and pressure depends on the balance of 2 antagonistic entities:
- The kinetic energy of the particles
- the strength of the attractions between particles
Attractions BETWEEN molecules.
Weaker!
Intermolecular forces
Attraction WITHIN molecules
Stronger!
Intramolecular forces
However intermolecular forces are able to control physical properties such as:
- boiling point
- melting point
- vapor pressures
- viscosities
The intermolecular forces that exist between NEUTRAL molecules.
Van Der Waals forces
Examples of van der waals forces from weakest to strongest
- London didpersion forces
- Dipole-Dipole interactions
- Hydrogen bonding
Other electrostatic attractions, polar molecule to ion attraction.
These are important in solutions of ions
Ion-Dipole
Other electrostatic attractions, ion to ion bonding
Ionic Bonding
Molecules that have permanent _______ are attracted to each other.
Dipoles
The ______ end of one dipole is attracted to the _____ of the other and vice-versa.
Positive
Negative
The more polar the molecule, the _______ is its melting point.
Higher
Attractions between an instantaneous dipole( uneven dispersion of electrons ) and an induced dipole.
-these forces are present in all molecules, whether they are polar or nonpolar
London dispersion forces.
The ease in which an electron colud can be deformed
Polarizability
The _______ of a molecule affects the strength of dispersion forces.
Shape
Larger atoms have larger electron clouds which are easier to _________.
Polarize
If two molecules are of comparable size, __________ interactions are probably the dominating force.
Dipole-dipole
If one molecule is much larger than another, _______ forces will likely determine its physical properties.
dispersion
Dipole-dipole interactions where H is bonded to N,O, or F
Hydrogen bonding
Hydrogen bonding arises in part from the high _____________ of nitrogen, oxygen ,and fluorine.
Electronegativity
Hydrogen bonding also arises when hydrogen is bonded to the very electronegative elements, the hydrogen nucleous is _____.
Exposed
Resistance of a liquid to flow.
Vsicosity
As intermolecular forces increases, viscosity _______.
Increases
Increase in temperature will _______ surface tension
Decrease
The greater the intermolecular forces, the ________ the surface tension.
Greater
Intermolecular forces that bond similar molecules to one another.
Cohesive forces
Intermolecular forces between a substance and a different surface
Adhesive forces
The greateradhesive forces allow water to be drawn up the narrow tube.
Capillary action
Energy required to change a solid at it’s melting point to a liquid.
Heat of fusion
Energy required to change a liquid at it’s boiling point to a gas
Heat of vaporization
Why is vaporization larger than fusion?
Breaks intermolecular forces completely
The stronger __________ the more energy you have to take to change states.
Intermolecular forces
Energy needed to vaporize 1 mole of a liquid.
Molar heat of vaporization
= 40.7 kJ/ mol
Energy that must be removed to condense 1 mole of a gas
Molar heat of condensation.
=-40.7 kJ/mol
Energy needed to melt 1 mole of a substance.
Molar heat of fusion
= 6.01 kJ/mol
Energy that must be removed to freeze 1 mole of a substance.
Molar heat of solidification
=-6.01 kJ/mol
What does adding heat to a system at the melting and boiling points result in?
Results in pulling the molecules farther apart from each other.
Kinetic energy is spent as ________ in state changes.
Potential energy
If kinetic energy is constant while changing states, so is _______
Temperature
What equation is used to calculate state changes when KE and temp. Are constant.
q= (
Energy while in a single state equation
q= (m)(c)(
Highest temperature that a liquid phase can form.
Critical Temperature
Pressure needed to cause liquefaction at the critical temperature.
Critical pressure
Weaker forces ➡️ ________ critical points
Lower
As more molecules escape the liquid, the pressure they exert _______.
Increases
In a closed system, the liquid and vapor reach a state in ehich liquid molecules evaporate and vapor molecules condense at the same rate.
Dynamic equilibrium
The temperature of a liquid at which it’s vapor pressure equals atmospheric pressure.
The boiling point
The temperature at which a substance vapor pressure is 760 torr.
Normal boiling point
The point in which all three states are in equilibrium
Triple point
Above critical temperature and critical pressure the liquid and vapor are indistinguishable from each other.
Critical point
Solids in which particles are in highly ordered arrangement
Crystalline
Solids in which there is no particular order in the arrangement of particles.
Amorphus
