Unit 3 Flashcards
What are the four type of solids?
- Molecular solids: Molecules held together by intermolecular forces
- Covalent solids: Extended structures held together by covalent bonds
- Ionic solids: Held together by electrostatic forces
- Metallic Solids : Metallic bond atoms, metal atoms as cations in the sea of ‘delocalized’ electrons
What is surface tension?
Amount of energy required to expand a liquid surface
What causes surface to contract?
Intermolecular attractions from below
What happens if surface tension is less?
IT occupies more area
What is cappilary action?
Rising of a liquid in a narrow space against the pull of gravity
What are the two types of forces liquids in a container face?
Cohesive forces: Forces between molecules
Adhesive forces: Forces aganist the wall like H and Sio2
What are the phase changes?
Solid —> liquid: Fusion (opp, freezing)
Liquid —–> vapour: Vapourisation (Condensation)
Solid —-> Gas: Sublimation (opp, deposition)
What happens to energy while braking bonds?
Energy is supplied, endothermic
To make bonds, energy is removed, exothermic
How is Enthalpy of Vapourazation compare to fusion?
delta H vap > delta H fus
When is a phase change spontaneous?
if free energy is negative.
Delta G = Delta H - T.deltaS
What determines if a process is spontaneous?
Both Delta H and delta S
When is entropy more?
If there is more randomness
S disordered > S ordered
H2O (s) ———-> H2O (l)
Delta S = S final - S initial
What happens if Delta S = S final - S initial = -ve?
The reaction will be spontaneous
How do you find the molecules with highest boiling points?
The one with the strongest intermolecular force is the one with highest boiling point
What is vapour pressure?
The pressure of gas in equilibrium (co-existing) with its liquid (or solid) at a specified temperature
What happens to vapour pressure with temp?
increases
What is boiling point?
The temperature at which vapour pressure of a liquid equals the external pressure.
What is normal boiling point?
boiling point at 1 atm.
What does vapour pressure depend upon?
Temp and strength of intermolecular forces
What determine the state of matter?
Intermolecular forces
What is equalization of pressure?
P atm = Phg
What happens to height if the density is more in a manometer?
The height increases
P = density.gravity.height of hg
What are the macroscopic properties of a compound?
T, V, n , P
What does the ideal gas law state?
- Gases are made up of tiny particles moving completely randomly.
- Total volume of particles very small compared to the size of container.
- Particles do not interact with each other.
- Particle collisions are elastic (no energy lost)
- Kinetic energy (K.E) increases with temp.
What is avg.KE for mol of gas?
K.E = 3RT/ 2Na ——> J/mol
How do you find the speed of particle?
u = root(3RT/M)
How is pressure created?
From gas particles colliding with container walls
When T and n is constant, How are P and V related?
V is inversely proportional to P
When P and n are fixed, how does V and T change?
V is directly proportional to T
How can you find mole fraction?
Xo2 = # mol of o2/ total moles
or
Po2/ Total P
What’s the differences in Effusion and Diffusion?
Effusion: Escape of gas through a hole
Diffusion: Movement of one gas through another.