C2: Phases and Thermochemistry Flashcards
Class 2
describe the phase change from:
solid to gas
sublimination
describe the phase change from:
solid to liquid
fusion/ melting
describe the phase change from:
liquid to gas
vaporization/ boiling/ evaporation
describe the phase change from:
gas to liquid
condensation
describe the phase change from:
liquid to solid
solidification/ freezing/ crystallization
describe the phase change from:
gas to solid
deposition
from solid > liquid > gas…
- heat is (absorbed/ released) ____
- temperature ____
- kinetic energy ____
- entropy ____
- intermolecular forces ____
- absorbed
- increases
- increases
- increases
- decrease
from gas > liquid > solid …
- heat is (released/ absorbed) ____
- temperature ____
- kinetic energy ____
- entropy ____
- intermolecular forces ____
- released
- decreases
- decreases
- decreases
- increase
in a phase transition diagram,
what is the heat of transition?
- heat of fusion?
-heat of vaporization?
the amount of energy required to to complete a transition
- the amount of heat that must be absorbed to change a solid into a liquid
- the energy absorbed when a liquid changes to a gas
what formula is used when trying to find the amount of heat within a phase transition diagram?
- if change in H and q are positive, heat is ____
- if change in H and q are negative, heat is ____
q= n x change in H(phase change)
where q= heat
n= # of moles of substance
- absorbed
- released
what is the formula for heat capacity?
q= mc x change in T
where q= heat
m= mass of the sample
c= specific heat of the substance
what is a calorie?
the amount of heat required to raise the temperature of 1 gram of water by 1 degree C
the specific heat of a substance depends upon its ____
phase (s, l, g)
what is the SI unit for energy?
joule
1 cal = ____ J
4.2
which 11 elements are gases at standard state conditions?
H2, N2, O2, F2, Cl2, He, Ne, Ar, Kr, Xe, Rn
which 2 elements are liquid at standard state conditions?
Hg and Br2
what are the 7 diatomic elements at standard state conditions?
- what is a good mnemonic to remember these?
H2, N2, O2, F2, Cl2, Br2, I2
- BrINCl HOF
for molecular solids..
- describe their structure
- are they malleable or rigid?
- are they conductors?
- are their BPs and MPs low or high?
- nonmetal atoms connected by covalent bonds, molecules have weak intermolecular forces
- soft
- no
- low
for ionic solids..
- describe their structure
- are they malleable or rigid?
- are they conductors?
- are their BPs and MPs low or high?
- metal cations and nonmetal anions from a crystal lattice locked in by electrostatic interaction
- rigid
- no
- high
for metallic solids..
- describe their structure
- are they malleable or rigid?
- are they conductors?
- are their BPs and MPs low or high?
- metal atoms form cations with delocalized valence electrons
- malleable
- yes
- medium
for covalent networks ..
- describe their structure
- are they malleable or rigid?
- are they conductors?
- are their BPs and MPs low or high?
- carbon or metalloid atoms form an extended network of covalent bonds
- rigid
- mostly no
- very high
in a phase transition diagram..
- which is on the x and y axis?
- inclines indicate ___ changes and plateaus indicate ____ changes. can both of these happen at the same time?
- the first incline indicates a ____ state, second a ____ state, and third a ____ state
- the first plateau indicates ____ and the second indicates ____
- x axis= heat (q), y axis= temperature
- temperature; phase. cannot happen simultaneously
- solid; liquid; gas
- fusion; vaporization
what is specific heat (c)?
- what does a large c mean?
- small c?
the amount of heat required to increase the temperature of 1 gram (or 1 mol) of a substance by by 1 degree C or 1K
- slower to heat or cool
- faster to heat or cool
what is heat capacity (C)
the amount of heat required to increase any amount of a substance by 1 degree C or 1K
in phase change diagrams…
- what goes on the x and y axis?
- what does it look like?
- what is the triple point?
- what is the critical point?
- what is supercritical fluid?
- x axis= temperature, y axis= pressure
- solid towards top left, then liquid in middle, then gas on bottom center
- where the 3 phases coexist
- when the phase ends
- when you go past the critical point where the phases do not exist
what does the phase diagram for water look like?
slightly negative slope
what happens to waters melting point when external pressure decreases?
it increases
the temperature of a substance is a measure of its internal ____ and is not changing
kinetic energy
why does a pot of boiling waters temperature remain constant despite the addition of heat?
the heat is used to break hydrogen bonds rather than increase the temperature
