Transcript Solutions & Other Mixtures

Vocabulary
 Solution: homogeneous mixture (can be S, L,
or G)
 Solute: substance that dissolves
 Solvent: substance in which the solute
dissolves
Vocabulary Cont’d
 Insoluble: substance that cannot be dissolved
 Soluble: substance that can be dissolved
 Miscible: 2 liquids mix completely
 Immiscible: 2 liquids that do not mix completely
Soluble vs. Insoluble
 “Like dissolves Like” Rule: Only substances
that are similar/alike will dissolve into one
another
 Polar and Polar (dissolve)
 Nonpolar and Nonpolar (dissolve)
 Polar and Nonpolar (do NOT dissolve)
 Water is Polar! (IMPORTANT)
Water
 Must be able to draw water!
Saturation
 Unsaturated: when a solution can hold more
solute and it does dissolve
 Saturated: when a solution cannot dissolve any
more solute
 Supersaturated: contains more solute than a
saturated solution at the same temperature
 extremely unstable and if a small amount of solute (seed
crystal) is added the excess solute quickly falls out of
solution (Example: hand warmers, rock candy, and
cloud seeding)
Solubility
UNSATURATED
SOLUTION
more solute
dissolves
SATURATED
SOLUTION
no more solute
dissolves
SUPERSATURATED
SOLUTION
becomes unstable,
crystals form
increasing concentration
Heat of Solution
 Endothermic: energy is put into the compound (feels
cold)
 Exothermic: energy is released from the compound
(feels hot)
 The overall change is the heat of solution
Dissolving & Solubility
 Factors that can effect the RATE (how fast/slow)
dissolving:
 Temperature
 Stirring/Agitation
 Surface Area
Temperature and Solubility
 Solids
 Increase Temp. will Increase Dissolving (Solubility)
Decrease Temp. will Decrease Dissolving (Solubility)
 Gases (Different from Solids)
 Increase Temp. will Decrease Dissolving (Solubility)
Decrease Temp. will Increase Dissolving (Solubility)
 Increase Pressure will Increase dissolving.
Decrease Pressure will Decreases dissolving.
Solids dissolved in liquids
Sol.
Gases dissolved in liquids
Sol.
To
As To , solubility
To
As To , solubility
Water and Oxygen
 Dissolved Oxygen – The amount of oxygen that is
dissolved in water
 If dissolved oxygen is too low, animal and aquatic
life is unable to survive and the water becomes
toxic
 Happens commonly in lakes and ponds during the
summer months
Temperature and Solubility
 Solubility of a gas increases as the external
pressure increases
 When pressure on the outside decreases some of
the gas escapes.
 Henry’s Law – At a given temperature the
solubility (S) of a gas in a liquid is directly
proportional to the pressure (P) above liquid
 S1P 2 = S 2 P 1
Practice
 If 0.24 g of a gas dissolves in 1.0L of water at 1.5 atm
of pressure, how much of the gas will dissolve if
the pressure is raised to 6.0 atm? Assume the
temperature is held constant.
 The solubility of a gas changes from 0.95 g/L to
0.72 g/L. If the initial pressure was 2.8 atm, what is
the final pressure?
Concentration
 How much solute is dissolved in a specific amount
of solvent or solution.
 Can be expressed as
 Percent by mass
 Percent by volume
 Molarity
Percent by Mass
 (Mass of solute/Mass of solution) x 100
 Used when a solid is dissolved in a liquid
 Mass of solution is equal to the mass of the solute
+ the mass of the solvent
Percent by mass problems
 In order to maintain a sodium chloride
concentration similar to ocean water, an aquarium
must contain 3.6 g of NaCl per 100 grams of water.
What is the percent mass of the solution?
 What is the percent by mass of NaHCO3 in a
solution containing 20 grams of NaHCO3dissolved
in 600 ml of water?
 You have 1500 grams of bleach solution. The
percent by mass of the solute is 3.62%. How many
grams of NaOCl are in solution?
 How many grams of solvent are in the solution?
Percent by Volume
 Usually describes solutions where both solute and
solvent are liquids
 Volume of solute/Volume of solution x 100
 What is the percent by volume of ethanol in a solution
that contains 35 ml of ethanol distilled in 115 ml of
water?
 If you have 100 ml of a 30% aqueous solution of
ethanol, what volumes of ethanol and water are in the
solution?
 What is the percent by volume of isopropyl alcohol in
a solution that contains 24 ml of isopropyl alcohol in
1.1 L of water?
Molarity
 Its unit is a M = mol/L
 Moles of solute/Liters of solution
 A 100.5 ml solution contains 5.10 grams of
Glucose (C6H12O6). What is the molarity of
this solution? The molar mass of glucose is
180.18 g/mol
 Calculate the molarity of 1.60 liters of a
solution containing 1.55 grams of dissolved KBr.
 What is the moles of solute in a solution with a
molarity 9.5 M and 25 mL of solution?
 What is the molarity of an aqueous solution
containing 40 grams of glucose in a 1.5 L of
solution?
 A 100.5 ml IV solution contains 5.10 grams of Glucose
(C6H12O6). What is the molarity of this solution? The
molar mass of glucose is 180.18 g/mol
Making a molar solution
 Using the molarity of the solution figure out how
many moles of the solute will be needed.
 Using the moles of solute, convert it to grams of
solute
 How many grams of CaCl2 would be dissolved in
1.0 liters of a .10M solution?
 A liter of 2M NaOH solution has how many grams
of NaOH?
 How many grams of CaCl2 should be
dissolved to make 500 ml of a .20M
solution?
 How many grams of NaOH are in 250 ml of
a 3.0M solution?
Diluting a stock solution
 Stock solution is a concentrated solution
M1V1 = M2V2
 What volume in ml of 2.00M CaCl2 stock
solution would you use to make 0.50 L of
0.300M calcium chloride solution?
 What molarity of a 300 mL KI stock solution
would you use to make 0.300 L of a 1.25 M KI
solution?
 If you dilute 20.0 ml of a 3.5M solution to
make 100.0 ml of solution, what would the
molarity of the diluted solution be?
 How many ml of a 5.0M H2SO4 stock
solution would you need to prepare 100 ml
of 0.25 M H2SO4?
Viscosity
 Fluids resistance to flow
 Fluid pours fast ________ viscosity
 Fluid pours slow ________ viscosity
Dissolving
 Ionization: The breaking up of a compound into
separate ions
 Electrolyte: A substance whose aqueous solutions
conduct electricity
 Nonelectrolyte: A substance whose aqueous
solutions do not conduct electricity
Name
Formula
Ionic /
Covalent
Soluble /
Insoluble
Electrolyte
or
Precipitate