solutions

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Chapter 13
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solutions

• Homogeneous
• Particle size- atoms, ions, molecules
• Does not separate on standing
• Cannot be separated by filtration
• Does not scatter light

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Colloids

• Heterogeneous
• Very large particles
• Does not separate on standing
• Cannot be separated by filtration
• Scatters light- Tyndal effect

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Suspensions

• Heterogeneous
• Very large particles
• Particles settle out
• Can be separated by filtration
• May or may not scatter light

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• Electrolyte- a solution that conducts
  electricitymust have ions present
• What system in the body uses electrolytes?

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• Solute- substance being dissolved
• Solvent- substance (medium) doing the dissolving

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• Substances that are mutually soluble- the
  smaller amount is the solute

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Random facts

• Water is the universal solvent
• Air is the solvent for all evaporated substances
• Alloy- mixture of 2 metals
• BRASS- zinc and copper
• 14 carat gold- gold and silver

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• Foams and emulsions are colloids
• (mayo, shaving cream)

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• What type of mixture is Fog? What is fog made
  of?
• Why do you drive with your lights on dim?

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Increase Rate of dissolving

• 1. heat- particles collide faster and more often
• 2. agitation- same as above
• 3. surface area- more area exposed to the
  solvent (crushing, grinding)

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solubility

• Amount of solute that can be dissolved in a
  specific amount of solvent

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Formation of a solution

• Solute breaks apart (endo)
• Solvent breaks apart (endo)
• Solute and solvent form and attraction(exo)
• Overall depends on which is greater- exo or endo

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• Solubility of a substance depends on
• bonding, pressure, temperature.

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Bonding effect

• Like dissolves like
• Polar dissolves polar
• Nonpolar dissolves nonpolar
• Review terms miscible, immiscible

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• Styrofoam cup demo

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• Why can oxygen gas O2 (nonpolar) dissolve in
  water (polar)? (This is an IMF question)

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Why drink red wine with red meat?

• Red meat is very fatty and this fat coats the
  tongue
• When the skin of the grape undergoes
  fermentation, tannic acid is produced
• Tannic acid has a polar end and a nonpolar end.
  The nonpolar end dissolves the fat off of the
  tongue

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• White wine(no grape skins) does not contain
  tannic acid, has a milder taste and is used with
  low fat meat(chicken)

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• Can I drink Welchs grape juice and get the same
  effect as red wine?

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Soap and detergent
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Soap and Detergent

• Water is polar Grease is nonpolar
• Soap is a long carbon chain compound that has a
  polar end and a nonpolar end.
• Nonpolar end sticks into the grease and the polar
  end can dissolve in water
• Soapy water forms a colloid and is washed down
  the drain

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• Soaps form precipitates with hard water. Water
  that contains ions such as Ca2, Fe3
• Detergents do not form precipitates so they wash
  away cleaner

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Pressure

• Effects gases
• Increase in pressure, increases solubility of gas
• Decrease in pressure, decreases solubility of gas
• Effervescence- rapid escape of a gas

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• Why do you tap on the mouth of a coke can?

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What is the bends to a scuba diver?

• A diver will have more gases dissolved in their
  blood. A diver has to pause when coming up to
  allow for the gases to be exhaled. Too fast
  ascent and the gases cannot be exhaled

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Temperature

• Increase in heat increases solubility of a solid
  and liquid
• Decrease in heat- increases solubility of a gas

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• Which goes flat faster?
• A opened Coke in the refrigerator or the coke
  left on the counter

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• What is thermal pollution in a lake? Why does it
  kill fish?

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• Boiling water
• Bubbles at the bottom of beaker- what are they
  and why did they appear?

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Concession Stands

• Trailer type- no electricity- how does the carbon
  dioxide get dissolved in the drinks?
• Resturant type- has electricity- how does the
  carbon dioxide get dissolved in the drinks?

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• Saturated- max amount of solute
• Unsaturated- less than max amount of solute

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• Supersaturated- using heat, the solute was
  dissolved and the solution was slowly cooled-
  contains more than the max amount of solute at
  the lower temperature.

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Solubility curve
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• What temperature is needed to dissolve 50 grams
  of potassium nitrate in 100 ml?
• How many grams of potassium chloride is needed to
  make a saturated solution at 80c?
• If a supersaturated solution was made with 80
  grams of KNO3 and cooled to 40c. How many grams
  of solute came out of solution when a seed
  crystal was added?

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• Looking at the graph, which substance is a gas
  based on the solubility graph?
• Which substance has the highest solubility at
  10c?
• What 2 substance has the same solubility at 72c?

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Expressing Concentration

• Be able to work the (blue) problem page
  completely and we should test next week.