Gen chem.txt

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    • author "me"
    • tags "Heat capacity, phase change, colligative properties"
    • description ""
    • fileName "Gen chem"
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    • Def phase
    • If all intensive macroscopic properties are constant, the system is homogenous and can be considered a phase
  1. What does it mean when a phase change occurs, and what are the two mechanisms capable of creating a phase change
    • When a phase changes, it means the internal energy has changed, or the space between molecules has changed.
    • Work and heat can change a phase
  2. Def heat capacity and give equation. what is a better name for it hint: more accurate description
    A measure of the energy needed to change the temperature of a substance. Or the amount of energy a substance can absorb before changing temperature. Puts an energy quantity to each thermal unit.

    • C=q/(dT)
    • Internal energy capacity
  3. How many types of heat capacities are there for any one substance. What are they
    • 2
    • Constant volume heat capacity
    • Constant pressure heat capacity
  4. Which is greater, Cv or Cp
    Cv > Cp
  5. What are the heat capacity equations and when do you use each? What are the symbols for each
    • q=C(dT): heat capacity of an over all system
    • q=mc(dT): specific heat capacity - heat capacity per unit mass
    • Specific heat symbol: c
    • Heat capacity symbol: C
  6. What is the specific heat capacity if water
    c(water)=(1 cal)/(g*Celcius)
  7. What is a calorimeter, what are the two types, and info do we get from each
    • Calorimeter: device used to measure energy change
    • Constant pressure: coffee cup calorimeter (because done at atmospheric pressure) tells heats of reaction
    • Constant volume: bomb calorimeter tells internal energy change
  8. Define heat of fusion and hear of vaporaization
    • Heat of fusion: solid to liquid phase change (melting/freezing)
    • Heat of vaporization: liquid to gas phase change (vaporization/condensation)
  9. Define triple point, critical temperature, critical pressure, critical point
    • Triple point: Single point where a substance can exist in equilibrium in all three phases simultaneously
    • Critical temperature: temp above which a substance cannot be liquified, regardless of the pressure added
    • Critical pressure: the pressure required to produce liquidification of a substance at critical temp
    • Critical point: point defined by a substances critical temp and pressure. Beyond this point, a liquid has gas a liquid characteristics
  10. What is a colligative property. What are these properties
    • Colligative property: a property which depends on n umber of particles involved only. Type does not change anything
    • 1. Vapor pressure
    • 2. Boiling point
    • 3. Freezing point
    • 4. Osmotic pressure
  11. Give equation for boilling point elevation. Why is this phenomena observed
    • dT=k(b)mi
    • k(b)= specific constant of substance being boiled
    • m= molality
    • i= van't Hoff factor = number of particles a single solute will dissociate into when put in solution
    • Nonvolatile solutes lower vapor pressure which in turn raises boiling point
  12. What is freezing point depression and how is it similar/different from boiling point elevation (bpe). What is the equation
    • Freezing point depression: change in melting point due to addition of solute
    • Same as bpe because a nonvolatile solute must be added to an ideally dilute solution for an effect
    • Different because it is not vapor pressure which is changed, but impurities in crystallization are created which lower freezing point
    • Same as bpe, but use k(f) instead of k(b)
  13. Define osmotic pressure. What is the equation.
    • Measure of waters desire to move into a substance due to osmosis
    • Pi=iMRT
Card Set:
Gen chem.txt
2013-08-22 20:48:14
Heat Capacity phase change colligative properties

Heat Capacity, phase change, colligative properties
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