Phases & Solutions Flashcards
the amount of heat required to raise the temperature of one unit mass of a substance by one degree
specific heat capacity
q = mcΔT
q= heat (Joules)
m = mass (grams)
c = specific heat value of a substance
ΔT = change in temperature (celcius or Kelvins)
When do we use heat of fusion/vaporization vs specific heat equations?
At phase changes: Use heat of fusion/vaporization forumla **q = nΔH **where n = # of moles. Units are kj/mol, and temperature remains constant
Between phase changes: use q = mcΔT
ex on pg. 73
he pressure of a vapor in contact with its liquid or solid form
vapor pressure
what are the temperature and pressure values for STP?
0°C (273K) & 1atm (760mmHg = 760 torr)
at STP, one mole of gas equals how many liters?
22.4L
True or False
Equal volumes of any twogases under the same conditions will contain the same number of gas particles
True
This is Avogadro’s Law, which states volume/moles is constant
List the assumptions of the kinetic molecular theory of gases.
The kinetic molecular theory assumes that gases act in an ideal fashion. Assumptions of this theory include:
- Gas particles have no volume
- The collisions between gas molecules are completely elastic, meaning that all kinetic energy is conserved
- The average kinetic energy of gas molecules is directly proportional to the temperature of the gas.
- Gases are made up of atoms that are in continuous, random motion
- Gases do not exert attactive or repulsive forces
In reality no gases obey these rules; they help predict gas behavior
When do gases behave most ideally? When do they deviate?
Gases deviate from ideal behavior at high pressures and low temperatures and behave most ideally at low pressures and high temperatures
Finish the equation
℉ = ____ C?
℉ = 9/5℃ + 32
on MCAT, you can calculate Fareinheight by doubling Celcius temperature
P1/T1 = P2/T2
Gay-Lussac’s Law
the number of moles of a given gas divided by the total moles of a gas in the mixture
mole fraction (Xgas)
Xgas = ngas/ntotal
properties that depend upon the concentration of solute molecules or ions, but not upon the identity of the solute
colligative properties
vapor pressure reduction, boiling point elevation, freezing point reduction, osmotic pressure
Name the law
vapor pressure reduction is expressed by which law?
Raoult’s law
Raoult’s Law defines the pressure above a mixture of liquids
Ptotal = XA+ PAO
PAO = vapor pressure of the solvent P = vapor pressure of the solution and XA is the mole fraction of the solvent
True or False
Reducing the vapor pressure of a solution is equivalent to increasing the boiling point
True
This is because The boiling point is defined as the temperature at which the vapor pressure equals the atmospheric pressure
describes an ion’s effect on the solubility equilibrium of a substance
common ion effect
If a soluble compound consisting of a common ion is added, it can decrease the concentration of that ion within the solution; this can result in a change in the equilibrium point of the solution.
