Transcript Atomic Structure and Theories

Solutions
Mixtures
(Varied Ratio)
Homogeneous
• True Solutions (Soluble)
• Solubility – Ability to
dissolve in solution
• (aq) See only 1 part
• Separated by evaporation
• Contains 2 Parts
1. Solute – The substance
that is being dissolved
2. Solvent – What is doing
the dissolving (Water)
Heterogeneous
• See Multiple parts
• Sand/ water, Dirt, Rocky
road ice cream
• Separated by filtration
Factors that effect Solubility
PANT
1. Pressure (g only) - P Solubility
2. Agitation – stirring (s) will Solubility
3. Nature of Solvent /solute
1. “Like dissolves like”
1. Water (polar) will dissolve Salts (Ionic-polar)
2. Water (Polar) does not dissolve fats –oils
(non-polar)
4. Temperature - T
Solubility (solids only)
T
Solubility (Gas…think soda)
3 Types of Solutions
Unsaturated, Saturated and Supersaturated
Table G
All BASED ON 100g OF WATER as the
SOLVENT
Unsaturated
1. A solution that contains less solute
than it can actually hold at any given
temperature
2. Said to be “below the line”
X
3 Types of Solutions
Unsaturated, Saturated and Supersaturated
Table G
Saturated
1. A solution that contains the
Maximum amount of solute that it
can actually hold at any given
temperature
2. Said to be “on the line”
X
Saturated
1. A solution that contains the Maximum
amount of solute that it can actually hold
at any given temperature
2. Said to be “on the line”
3. If more solute is present, a precipitate
(ppt) will form on the bottom
4. Seen ONLY in saturated Solutions
Problem:
At 60’C, 128 g of NaNO3 will
dissolve in 100g of water. If
this sample of water is cooled
to 35 ‘C, How much NaNO3 will
still be dissolved in the water?
How much ppt will form?
X
3 Types of Solutions
Unsaturated, Saturated and Supersaturated
Table G
Super Saturated
1. A solution (Forced) that contains
More solute than it can actually
hold at any given temperature
2. Said to be “above the line”
X
Making a Super Saturated Solution
Phase Equilibrium
Seen only with Saturated Solutions
Rate of dissolving = Rate of Crystalizing
Phase Equilibrium
Seen only with Saturated Solutions
Table G - Solubility Curves
1. All based on 100g of Water as the Solvent
2. So…. If you have 200 g of water, you must
double all the values
3. If you have 300g of water,
_______________________________
4. If you have 50g of water ,
_______________________________
Concentration
1. Measured by Molarity
1 Gram of H2O = 1ml
1L = 1000ml
Parts Per Million (ppm) = Mass of solute x
Mass of Solution
1,000,000
Below are the two equations needed to perform the concentration calculations
needed for the first 12 questions of this sheet. You may recognize them from
the back cover of your Reference Tables.
What is the molarity of a solution which has a total volume of 100
mL and contains 3 moles of NaCl?
What is the molarity of a solution that contains 1.5 moles of
NaNO3 in 2.5 Liters of solution?
A solution is made that contains 1.25 moles of sugar in 175 mL of
solution. What is the molarity of the solution?
A 4 molar solution of ammonium chloride will contain how many
moles of solute in 100 mL of solution?
Given a 250 mL sample of a solution that is 0.25 molar, how many
moles of the solute do you possess?
How many moles of KNO3 are needed to make 0.750 L of a
3.25 M solution?
What volume of solution, measured in liters, is necessary to
obtain 1 mole of solute if the concentration of the solution is
1.25 M?
If a sample of solution contains 1.5 moles of sodium
hydroxide, and the concentration of the solution is 0.8 M,
then what volume of the solution do you possess?
Given a 1.4 M NaCl solution, 0.90 moles of sodium chloride
would be contained in how many milliliters of the solution?
If you have made a 455 ppm solution, how many grams of
sodium chloride are in 1000 grams of the solution?
When 0.0043 grams of O2 is dissolved in 100 mL of water,
what is the concentration of the solution, measured in ppm?
A substance has a solubility of 350 ppm. How many grams of
the substance are present in 1.5 L of solution?
volum e_ solute
%Volum e
*100%
volum e_ solution
13. What is the percent by volume of ethanol if 50.0 mL of ethanol is diluted with water to form a
total volume of 300.0mL?
14. How many milliliters of a liquid were used to make a 13% solution with a total volume of 80 mL?
15. What volume of a 35% solution of alcohol can be made using 20 mL of the solute?
Mass _ part
%m ass
*100%
Mass _ whole
16) A rock contains 15 grams of calcium carbonate and 85 grams of other substances, what is
the composition of the rock as measured in percent by mass?
Molarity by Dilution
1. Done using the Titration equation but make a change!
M 1 V 1 = M2 V 2
Electrolytes
• Substances that when put into solution, will
dissociate in solution
• DISSOCIATION – the ability to break up into
their component ions in solution
• It is the “Mobile Ions” that give the solution
the ability to conduct electricity
• Ionics (Polar Substances) have this ability
• Good Electrolytes (Salts, Acids and Bases)
• Non-electrolytes (covalent compounds)
Remember Molecule – Ion Attraction
H
O
Cl
H
+
Na
• This is why Polar substances like ionic compounds
dissolve in and dissociate in water (polar)!
What other type of attraction do you see at work
here?
Colligative Properties