solutions chapter 15. chemcatalyst:___.___ think back to marking period one and define in your own...
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SOLUTIONSChapter 15
Chemcatalyst:___.___• Think back to marking period one and define in your own
words the difference between a homogeneous and a heterogeneous mixture?
Mixtures
HOMOGENEOUS
• Uniform throughout• 1 continual phase
• Example: solutions like salt water
HETEROGENEOUS
• Not uniform throughout• Multiple phases
• Example: Oil and water
Other Heterogeneous Mixtures:
Suspension
• Particles are much larger• Do not stay suspend
indefinitely
• Particles begin to separate out
• Multiple phases
• Example: Clay in water or sand in water
Colloids
• Particles are medium-sized• Spread out and dispersed
• Cloudy or milky appearance
• Examples: Whipped cream, glue, milk, or mayo
Did you know?• Colloidal solutions, like fog, disperse or separate light!
• It is called the Tyndall effect!
• When light passes through it, the particles reflect or scatter the light in all different directions!
Mini Lab on types
PROPERTIES OF SOLUTIONSChapter 16
Chemcatalyst: __.__• Predict and explain whether sugar will dissolve faster in
iced tea or hot tea.
• Follow up: Which would dissolve faster cubed sugar or granular sugar?
Solutions, eh? • Solutions are homogeneous mixtures!
• Meaning same throughout
• They can be solids, liquids, or gases!
How do I make this said solution…?
SOLUTE
• The dissolved particles in a solution is known as a solvent
• The solute will become dispersed throughout the solvent
• Can be solids, liquids, or gases
SOLVENT
• The dissolving medium is the solvent
• The solvent dissolves the solute
• Can be solids, liquids, or gases
A solution has a solute and solvent
Why do you stir sugar into your tea?
Agitation• Stirring or shaking speeds up the solution process
• More of the solute will be brought into contact with solvent
• Only affects the time it takes to dissolve, not the amount of solute dissolving
• Insoluble will always be insoluble
Back to the C.C
Hot or cold tea dissolves sugar faster?
Temperature• High temperature, more kinetic energy molecules move
faster
• The rapid motion is an increase in collisions between the solvent and the solute
http://www.youtube.com/watch?v=cckAwavEKA0
Back to the C.C. follow upSugar cube or granular sugar dissolves faster?
Particle Size of Solute• The smaller the particles, the greater surface area to
collide with the solvent
• The more surface area, more collisions and the faster rate of dissolving
Chemcatalyst __.___• What does it mean if something is soluble?
• Give an example
Solubility• The amount of solute that dissolves in a given quantity of
solvent at a given temperature and pressure
• This amount creates a saturated solution
• Solubility is expressed in g/100 g H2O
Think about this…
Kool aid man, “Ohh yeaa” ©
• What if I put the entire container in?
• What does it look/taste like if I do not put all of it in?
Supersaturated vs Unsaturated
Supersaturated
• A solution that contains more solute that is able to dissolve
• Only so much will dissolve, the rest will be solid on the bottom
• Ex: Adding too much of the Kool Aid powder, rock candy
Unsaturated
• A solution that contains less solute than the saturated solution
• Ex: Not adding enough Kool Aid Powder
Did you know?• Miscible means soluble or the ability to dissolve in one
another• Example: Water and Ethanol
• Immiscible means they are insoluble• Example: Oil and water
Mini Lab • Solution and solubility mini lab
• Play at end of lab• http://www.youtube.com/watch?v=ghKUzh8l_t0
Factors affecting solubility
Temperature
• In general, the solubility of a solid increases as the solvent is heated
• In general, the solubility of a gas increases as the solvent is cooled
Pressure
• Little effect on the solubility of solids and liquids
• If the pressure above the liquid increases, the solubility of the gas increases
Henry’s Law• At a given temperature, the solubility of a gas in a liquid is
proportional to the pressure above the liquid.
• If the pressure increases, the solubility increases
• Example: Carbonated soda (CO2)
Chemcatalyst: __.___• What would you need to change?
• A saturated solution to an unsaturated solution• A saturated solution to a supersaturated solution• An unsaturated solution to a saturated solution
What is concentration?• The measure of the amount of solute that is dissolved in a
given solvent
• Depending on the amount it can be classified as dilute or concentrated
Concentration
Dilute solution
• A small amount of solute dissolved
Concentrated solution
• Large amounts of solute dissolved
*** Only qualitative, not QUANTITATIVE
If that’s qualitative, then how do we measure concentration?
Molarity (M)• Molarity is the number of moles dissolved in 1 liter of
solution
• Referred to a molar concentration or solution
• Units are moles/liter or represented as M (molar)
• Molarity = Moles of the solute
Liters of the solution** Volume must be in liters
Let’s calculate the molarity together!• What is the molarity of a solution that contains 0.70 mol of
NaCl in 250. mL?
• Molarity=
Try this one on your own:• IV fluid has 0.15 moles of saline solution in it, what would
the molarity be for 200. mL?
• Molarity=
How do you make a solution?
• Mini Lab• http://www.youtube.com/watch?v=cckAwavEKA0
Chemcatalyst: __.__• What would the molarity be a solution that has 0.0500
moles of solute and a given volume of 400. mL?
• Show work with units, try your best with SF
Dilution• To create a dilution, the number of moles of solution will
be reduced
• A dilution is created from a concentrated solution
• We use this equation:
M1V1 =M2V2
1 is initial conditions( concentrated solution)
2 is final conditions (dilute “new” conditions)
Let’s do this together!
• How many mL of 2.00 M MgSO4 solution must be diluted to prepare a 100.0 mL of 0.400 M MgSO4 ?
• M1= 2.00 M
• V1= ? mL
• M2= 0.400 M
• V2= 100.0 mL
M1V1 =M2V2
(2.00 M) V1= (0.400 M) (100.0 mL)
V1= 20.0 mL
Try this one on your own!• How many mL of a solution of 4.00 M KI are needed to
prepare 250.0 mL of 0.760 M KI
• M1= 4.00 M
• V1= ? mL
• M2= 0.760 M
• V2= 250.0 mL
M1V1 =M2V2
(4.00 M) V1= (0.760 M) (250.0 mL)
V1= 47.5 mL
Chemcatalyst: __.__• How many moles of ammonium nitrate are in 355 mL of a
0.425 M solution
0.151 mol
• How many mL of a 1.0 M solution to prepare 250. mL of a 0.20 M solution?
50. mL