Topic 3 Flashcards
What are the physical properties of Gases?
Highly compressible
Infinitely miscible
Thermally expandable
Low density
How does a Gas exert pressure on its environment?
The molecules are in constant motion and hit the walls
What is the formula for Pressure?
Pressure = Force (N) / Surface Area (m^2)
What are the units of pressure?
N/m^2 = Pascal (Pa)
mmHg (torr)
atm
What is the equivalence of the different type of pressures?
1 atm = 760mmHg = 101325 Pa = 760 Torr
What are the 3 Gas laws called?
Boyles Law
Charle’s Law
Avogadro’s Law
What does Boyles Law state?
At a constant temperature, pressure is inversely proportional to volume. If pressure increases volume will decrease
What is the formula for Boyles Law?
P1V1=P2V2
What does Charles’ Law state?
At a constant pressure, temperature is directly proportional to volume
What is the formula for Charles’ Law?
V1/T1 = V2/T2
How do you fine Temperature in Kelvins from Celcius?
T(k) = T(c) + 273.15
What does Avogadro’s Law state?
Temperature is directly proportional to volume, at a constant pressure
What is the Formula for Avogadro’s law?
V1/n1 = V2/n2
When is each R constant used?
- 314 when pressure is in pascals
0. 08206 when pressure is in atm
When is the formula for Density?
d= m/v
What is Daltons law of Partial Pressure?
In a mixture of non-reacting gasses the total pressure is the sum of the partial pressures of the individual gasses
What are the 5 parts of kinetic molecular theory?
- Gasses are made of particle with no defined volume
- Particles are in continuous random motion
- Particles move independently and experience no inter-particle forces
- Particles collide with each other and the walls of the container
- The average kinetic energy is the same for all gasses at a given temperature
What is the formula for the pressure of 1 particle moving in 1 dimension?
P = (mu^2) / v
What is the formula for the large volume of particle moving in 3-D?
(2/3) [n(N0.5mu^2)]/v
What is the formula for kinetic energy of one particle of gas?
(1/2)mu^2
What is Diffusion?
The process by with a substance mixes with one or more substances following the movement of particle
What does it mean if PV/RT > 1?
The effect of particle volume dominates
What does it mean if PV/RT < 1?
The effect of inter-particle attraction dominates
What occurs in real gasses the Kinetic Molecular theory fails to comply with?
- Particles in real gasses experience weak inter-particle attraction
- Particles in a real gas occupy a finite volume
What does the Van der Walls equation take into account?
The inter-particle attraction and the volume occupied by gas particles
What are the properties of Solids?
No freedom of movement
Keeps its shape
Very close together and inter-particle forces are strong
Dense
What are the properties of liquids?
Lack rigidity and compressibility
Take shape of container
Viscosity of liquid can be measured
Density is higher than that of a gas
What are the Permanent Dipoles?
Ion Dipoles
Dipole - Dipole
H- bonds
What are the Temporary Dipoles?
Ion induced Dipole
Dipole induced Dipole
London Dispersion
What is an Ion Dipole?
An attractive force between an ion and a neutral molecule
What is a Dipole-Dipole?
Attraction of two permanent dipoles of different molecules
What is A H-Bond?
The attraction of a hydrogen atom of water that is attracted to a nitrogen, oxygen, or flourine
What is an Ion Induced Dipole?
A weak attraction that results when an ion induces a dipole in an atom or non polar molecule by disrupting the arrangement of electrons
What are the properties of Solids?
No freedom of movement
Keeps its shape
Very close together and inter-particle forces are strong
Dense
What are the properties of liquids?
Lack rigidity and compressibility
Take shape of container
Viscosity of liquid can be measured
Density is higher than that of a gas
What are the Permanent Dipoles?
Ion Dipoles
Dipole - Dipole
H- bonds
What are the Temporary Dipoles?
Ion induced Dipole
Dipole induced Dipole
London Dispersion
What is an Ion Dipole?
An attractive force between an ion and a neutral molecule
What is a Dipole-Dipole?
Attraction of two permanent dipoles of different molecules
What is A H-Bond?
The attraction of a hydrogen atom of water that is attracted to a nitrogen, oxygen, or fluorine
What is an Ion Induced Dipole?
A weak attraction that results when an ion induces a dipole in an atom or non polar molecule by disrupting the arrangement of electrons
What is a Dipole Induced Dipole?
a weak attraction that results when a polar molecule induces a dipole in an atom or in a non-polar molecule by disturbing the arrangement of electrons in the non-polar species
What is a London Dispersion?
A temporary attractive force that results when the electrons in two adjacent atoms occupy positions that make the atoms form temporary dipoles
What are the characteristics of London dispersion forces?
Create an instantaneous intermolecular (or interparticle) attraction that is short lived and weak. The higher the atomic mass, the higher the probability for the formations of instant dipoles of higher magnitude. Not strong enough to lead to the formation of liquids
What is the polarizability?
How easy it is for an electron cloud to be distorted
What is the trend in boiling points of noble gasses?
Boiling point increases as you move down the group because intermolecular forces increase
What allows for an electron cloud to be easily distorted?
An increase in the size of the electron cloud which is increased as the size of a atom increases
What does a large electron cloud mean?
The bigger the electron cloud in a molecule, the more polarizable it is, therefore, the stronger the intermolecular forces.
Hoe does a linear molecule compare to a branched molecule?
Linear molecules are more polarizable so they have higher intermolecular forces and they can stack more easily than branched molecules
What are the factors to consider when deciding the intensity of intermolecular forces of Non-Polar compounds?
Molar masses Molecular shape (when MM are comparable)
What are the factors to consider when deciding the intensity of intermolecular forces of Non-Polar and polar compounds?
The polar compound has stronger intermolecular forces
What are the factors to consider when deciding the intensity of intermolecular forces of Polar compounds?
Strength of permanent dipole interactions
H-bonding or not
What is Surface tension?
The resistance of liquid to increase its surface are, it is the reason why many liquids form spherical droplets
What does a high surface tension mean?
Strong intermolecular forces
What can is used to compare intermolecular forces?
Molar mass and IMF
What does a large molar mass mean?
Large electron cloud which means high intermolecular forces
What is is Capillarity?
The spontaneous rising and descent of a liquid in a capillary tube
What is Wetting?
The ability of a liquid to maintain contact with a surface
What is the competition between in Wetting and Capillarity?
Cohesive and Adhesive force
What are Cohesive forces?
The forces between the molecules of a liquid
What are adhesive forces?
The forces between the molecules of a liquid and those on the surface of the capillary tube
What occurs when cohesive forces are stronger than adhesive forces?
A convex meniscus forms and the liquid descends
What occurs when adhesive forces are stronger than cohesive forces?
The liquid will rise in the tube creating a concave meniscus
What is Viscosity?
The resistance of a liquid to flow
What does a high viscosity mean?
High intermolecular forces
What is the general rule for solubility?
In general like substances dissolve like substances
What needs to happen in order for substances to dissolve?
Solute-Solvent forces have to be dominant over solute-solute and solvent-solvent forces
What are the Physical properties of solids?
Solids have definite volumes and shapes. The particles are tightly packed and do not have freedom of movement
What are the two general categories of solids?
Crystalline solids and Amorphous solids
What are Crystalline Solids?
Highly ordered assembly their components in a well defined pattern
What are Amorphous solids?
Random assembly of components
What are the Two types of Crystalline Solids?
Discrete Molecular Structures
Extended Structures
What are the two types of Discrete Molecular Structures?
Non-polar and Polar
What are the three types of extended structures?
Ionic
Covalent
Metallic
What is the structure of Crystalline Solids?
Highly symmetrical unit cells that repeat themselves indefinitely in 3 dimensions
What Coordination number?
The number of neighbors that a central particle is in contact with
What is the CN of a Simple cubic lattice?
6
What is the CN of Body centered lattice?
8
What is the CN of a Face centered lattice?
12
What is the Net number of particles that belong to a Simple Cubic Lattice?
1
What is the net number of particles that belong to a Body Centered Lattice
2
What is the net number of particle that belong to a Face Centered Lattice?
4
How many atoms is one atom in contact with in a square packed structure?
4 other atoms
How many atoms is one atom in contact with in a 2D close packed structure (hexagonal)?
6 other atoms
Where is layer B placed in 3-D Hexagonal Close Packing?
On top of the tetrahedral voids of layer A
Where is the second Layer A placed in 3-D Hexagonal Close Packing?
On top of the tetrahedral voids of layer B
What is the pattern of 3-D Hexagonal close packing?
ABAB
What is a Tetrahedral void?
A void that has 3 on each side and one on top
What is an Octahedral void?
A void that has 3 on top and 3 on the bottom
What is the contact number in Hexagonal Close packing?
- 6 in the same row, 3 on top, 3 on the bottom
Where does layer B sit in Cubic close packing?
On the tetrahedral voids of layer A
Where does layer C sit in Cubic close packing?
On the octahedral voids of layer B
What is the Contact number of Cubic close packing?
- 6 in the same row, 3 on top, 3 on the bottom
How do you find the mass of one unit cell?
(# of atoms x molar mass)/ avogadro’s #
What is sublimation?
Solid to Gas
Which curve is the Sublimation curve?
The curve that separates solid and gas
What is the Melting or Fusion curve?
The line that separated Solid and Liquid
What is the Vaporization curve?
The curve that separated liquid and gas
What is the Triple Point?
The point where all three states co-exist in equilibrium
What is the Critical point?
When a substance that has properties of both liquid and gas and interference between liquid and gas is lost
