Chem Unit 2
Terms
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True or False:
A high concentration doesn't effect the vapor pressure very much. - False. A high concentration changes the vapor pressure considerably.
- Vapor pressure of a solution is ______ then the pure liquid.
- Less
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True or False:
Normal boiling point is different for the pure liquid then for the solution. - True
- Properties that change as a function of the number of solute particles are called __________ properties.
- Colligative
- List the four colligative properties:
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1. Vapor Pressure
2. Boiling Point
3. Freezing Point
4. Osmotic Pressure - Osmosis
- The migration of solvent molecules through a differentiating membrane from lower concentration to higher concentrations.
- The larger the gap is between the high concentration substance and the lower concentration substance the ___________ the pressure is.
- Greater
- As the concentration of a solution increases, the vapor pressure _________.
- Decreases
- As the concentration of a solution increases, the osmotic pressure _________.
- Increases
- As the concentration of a solution decreases, the boiling point __________.
- Decreases
- As the concentration of a solution decreases, the freezing point _________.
- Increases
- The pressure at which an equilibrium is reached for the migration of solvent molecules through a differentiating membrane is the ___________ pressure.
- Osmotic
- If the mole fraction of a solvent was 0.5, the vapor pressure would go down by ________.
- Half
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K-sub-f is the:
K-sub-b is the: -
Molale freezing point depression constant.
Molale boiling point elevation constant. - The change in osmotic pressure is symbolized by the symbol ____.
- Pi
- The formula for the change in osmotic pressure:
- MRT
- The formula for the change in boiling point is:
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Delta T (because it is a change of temperature)
(K-sub-b)(m) - The formula for the change in freezing point:
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Delta T (because it is a change of temperature)
(K-sub-f)(m) - In ionic solutions, what is different with the calculations to determine the change in osmotic pressure, boiling point or freezing point?
- An ionic molecule breaks apart into two particles, so 1.3 m of NaCl actually equals 2.6 moles of particles.
- K-sub-f and K-sub-b are both measured in:
- degrees C/molal
- Describe how you would go about finding the molar mass of a molecule using colligative property data:
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1. Get concentration
2. Determine moles of solute
3. Knowing the mass and moles, determine molar mass. - Delta H represents:
- Enthalpy (heat content)
- If delta-H is positive, the reaction is ____thermic. If delta-H is negative, the reaction is ____thermic.
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Endo
Exo - A __________ reaction takes place on it's own.
- Spontaneous
- Delta-G represents:
- The free energy of a solution.
- If delta-G is negative, the order of the substance is _________ in the reaction.
- Decreasing
- Less order makes the reaction _______ spontaneous.
- More
- What is the formula that represents the change in total energy in a reaction?
- Delta G = Delta H - T(Delta S)
- If Delta G is positive, there is a(n)____________ in order.
- Increase
- At equilibrium, delta G is ________.
- Zero
- If DeltaG is ____________, the reaction is ____________.
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Negative = Spontaneous
Positive = Nonspontaneous - As the temperature increases, the entropy term becomes ________ significant.
- More and more
- If heat is released in a reaction, it is said to be ________ ________.
- Enthalpy driven
- At high temperatures, enthalpy can take over and a reaction can become _________ _________.
- Entropy driven
- Unsaturated hydrocarbons are AKA:
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Alkenes (double bonds) and
Alkynes (triple bonds) - Saturated hydrocarbons are AKA:
- Alkanes
- ______ groups on carbon chains create alcohols.
- OH
- Groups that are attached onto carbon chains are called _________ groups.
- Functional
- A condensation reaction creates __________ molecules.
- Water
- An amino acid contains a _______ group and a ________ group.
- Amine group and acid group
- List the four factors that affect rates of reactions.
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1. Temp
2. Pressure and concentration
3. Catalysts
4. State of matter - A ________ changes the activation energy.
- Catalyst
- Activation energy
- The energy required to get a reaction going.