Transcript Concentration & Dilutions

Today…
 Get
Out:
 Nothing
 Our
Plan:
 Airbag
Lab (Reading & Initial
Measurements)
 Homework
Planner):
 Nothing
(Write in
Today…
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Get Out:
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Goggles, Lab Handout, Bag of Supplies
Our Plan:

Airbag Lab
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Quick Reminders:
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Come up with a design FIRST (use 2.50 g of baking soda
and 29.8 mL of vinegar for each trial).
Make sure to time the reaction from beginning to end AND
measure the height of your bag for EVERY TRIAL!
After you have a design that you like, tinker with the
amounts of vinegar and baking soda until you have the
perfect combination.
You MUST have a design by the end of class!
Homework (Write in Planner):
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Nothing
Today…
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Turn in:
 Nothing
Our Plan:
 Airbag Lab – Packet due TODAY!
 Must Have:
 Calculations
p. 3 & 4
 Trial(s) with Speed & Height/Diagram p. 5
 At least 6 trials changing amount of chemical
Final Tests the last 20 minutes
Homework (Write in Planner):
 Enjoy your Weekend
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Check this out…
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Oobleck
http://www.youtube.com/watch?v=
1nX8jvj_jOk
Today…
Turn in:
 YOU NEED YOUR TEXTBOOK
TODAY AND NEXT CLASS!
 Our Plan:
 Video Clips
 Stop the Process Reading & Activities
 Homework (Write in Planner):
 Finish AT LEAST the first two
pages from the packet (2 & 3).
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Here’s some of what you’ll learn…
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http://www.youtube.com/watch?v=
PBF_t8Zt9AU
Page 4, box #1
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http://vimeo.com/2670546
Today…
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Turn in:
 YOU NEED A TEXTBOOK TODAY!
 Get out Stop the Process & Clicker
Our Plan:
 Clicker Review
 Immiscible Love Story
 Set Up Borax with your table group
 Finish Stop the Process Reading
 Quick Review of Saturation
 Supersaturated Lab
 Wrap Up – Mix-Pair-Share
Homework (Write in Planner):
 Finish Stop the Process
Quick Review – Grab a Clicker
In salt water what is the solute,
salt or water?
 In lemonade what is the solvent,
water, lemon juice, or sugar?
 Which kind of Kool Aid has the
MOST SOLVENT; very sweet or
barely sweet?
 What do we call a solution that can
conduct electricity?
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Solution Formation Animation
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http://www.mhhe.com/physsci/che
mistry/essentialchemistry/flash/mol
vie1.swf
Immiscible Love Story
Steve Spangler Video – Stop the
Process Last Box
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http://www.stevespanglerscience.co
m/experiment/instant-hot-ice
Saturated vs. Unsaturated
Video Clip of Supersaturation – Hot Ice
Lab Time!
Wrap Up – Mix-Pair-Share
1.
2.
3.
4.
5.
How can you tell if a solution is
saturated, unsaturated, or
supersatured?
What do you add to a solution to make
it supersaturated?
What is an example of two things that
are immiscible?
What does it mean if something is
deliquescent?
In Jello, what is the solute and what is
the solvent?
Today…
Turn in:
 Stop the Process
 Our Plan:
 Review
 Finish Supersaturated Lab
 Molarity POGIL
 Wrap Up – High Five
 Homework (Write in Planner):
 Finish POGIL
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Review– Mix-Pair-Share
1.
2.
3.
4.
5.
How can you tell if a solution is
saturated, unsaturated, or
supersatured?
What do you add to a solution to make
it supersaturated?
What is an example of two things that
are immiscible?
What does it mean if something is
deliquescent?
In Jello, what is the solute and what is
the solvent?
Wrap Up
As a team, what are 5
things that you learned
today?
Saturated vs. Unsaturated
Today…
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Turn in:
 Get Out Index Card/Sticky Note
and number 1 - 8
Our Plan:
 Molarity Quick Review
 Molarity Quiz
 Finish POGIL
 Start Crossword Puzzle, if time
Homework (Write in Planner):
 POGIL, if not finished
Vocab Review

Which word from the word wall am I?
1.
2.
3.
4.
5.
6.
When you add water to Kool-Aid and
make it less concentrated.
Two substances that can’t mix, like oil
and water.
Milk, cheese, fog, mayonnaise
If you add a seed crystal and a solution
crystallizes.
In ocean water, water is the _____.
A substance that cannot conduct
electricity.
Molarity Review
M = mol/L
7.
8.
What is the molarity of a
solution with 3.4 grams of HCl
in 157 mL? (0.59 M)
What volume of solution would
be made from 2.1 moles of
3.72 M solution? (0.56 L)
Today…
Turn in:
 Get out POGIL
 Our Plan:
 Finish POGIL
 Molarity Activity
 Homework (Write in Planner):

POGIL Due next class
 State Assessment Next Class
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Today…
Turn in:
 Nothing
 Our Plan:
 State Assessment
 Molarity Review Activity
 Molarity Quiz
 Homework (Write in Planner):


Nothing
Today…
Turn in:
 POGIL & Grab a Clicker
 Our Plan:
 Vocab Crossword Puzzle (25 min)
 Dilution Notes
 Rainbow in the Blue Lab
 Clicker Review
 Homework (Write in Planner):
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Finish Lab Questions & Crossword
Review Time
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Clicker Review
What volume of solution would be
made if you have 78.9 g of HCl and
want to make a 3.72 M solution?
What is the percent by mass of a
25.6 g Kool Aid solution with 3.87
g of Kool Aid powder?
Dilution
 Definition-
making a
solution less concentrated
 Equation
 where
– M1V1=M2V2
M= molarity &
V=volume
Example
What
volume of
concentrated HCl
(12.4M)should be used
to make 250mL of 4M
HCl?
Example
 What
volume of water should be
used ?
 Making
250mL
Example 2
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12mL of an unknown
concentration of sulfuric acid was
used to make a 500mL sample of
0.56M sulfuric acid. What was the
concentration of the unknown?
Stop!
Complete
the
example problems
in your
notebooklet.
LAB TIME!!!
Complete
the rainbow
out of the
blue lab
Wrap Up
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Clicker Review 2
Clicker Review 3
Today…
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Turn in:
 Crossword Puzzle - basket
 Dilution Lab - basket
Our Plan:
 Clicker Review
 Daily Challenge
 Notes
 Worksheet #2
Homework (Write in Planner):
 Worksheet Due next class
Daily Challenge
In
the winter when the
streets are going to
become icy, what does
the city do? Why do
they do it?
Colligative
Properties
Molality
Concentration
of a
solution expressed as
moles of solute per
kilogram of solvent
(m)
Equation
m=
moles solute
mass of solvent (kg)
Example
A
solution was prepared by
dissolving 17.1g of sucrose
in 125g of water . Find the
molal concentration of this
solution.
 m= moles solute
mass of solvent (kg)
Example continued …
Find moles of solute17.1 g sucrose x 1mole = 0.0500 mole
342.34 g
 Find kg solvent –
125g x 1kg = 0.125kg
1000g
 Use equation- 0.0500 mole = 0.400 m
0.125kg
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Try It Out
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Do #1 & #2 on your worksheet
Colligative Property
Properties
that
change when
solute particles are
added.
Vapor Pressure Lowering
 Vapor
Pressure is the
pressure caused by molecules
that have escaped from the
liquid phase to the gaseous
phase.
 It is the tendency of
molecules to evaporate.
Vapor Pressure Lowering
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Liquid molecules at the surface of a
liquid can escape to the gas phase when
they have enough energy.
By adding a solute the amount of surface
area for the escaping solvent molecules
is less (solute particles take up space).
The solvent molecules have a lower
probability to evaporate (pressure is
lower)
Vapor Pressure Lowering
 Example
– water vs. salt water
Freezing Point Depression
 In
order for a liquid
to freeze it must
form crystals.
 When a solute is
added, it disrupts
the solution’s
ability to form
crystals.
Freezing Point Depression
Example
–
Putting salt on
icy sidewalks
in the winter
Another Example
 Antifreeze
in cars
 Insects & Reptiles– survive
freezing temps by producing
a form of antifreeze
(alcohols and sugars)
 Species of fish in the
Antarctic
Freezing Point Depression
The
Equation
Δtf = Kfm
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Δtf (freezing point depression) is the
difference between the freezing points of
the pure solvent and a solution
Kf is the molal freezing point constant
m is the molality
Boiling Point Elevation
Because
the
vapor pressure
is lower, it takes
a higher
temperature to
boil a solvent.
Boiling Point Elevation
Adding
salt to
water when
making pasta?
 NO!
Would take 1.3
lb of salt to raise
temperature 2
degrees
Boiling Point Elevation
 Example
– antifreeze in a
car’s radiator
 Serves as a coolant in
the summers that keeps
it from “boil overs”.
Boiling Point Elevation
The
Equation
Δtb = Kbm
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Δtb (boiling point elevation) is the
difference between the boiling points of
the pure solvent and a solution
Kb is the molal boiling point constant
m is the molality
Colligative Sample Problem 1
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What is the freezingpoint depression of
water in a solution of
0.0500 mol of sucrose
(C12H22O11), and 200 g
of water?
Problem 1
Δtf = Kfm
Δtf = ?
Kf
m
= -1.86 ○C/m (packet)
= mol solute/kg solvent
= 0.0500 mol/0.2 kg
= 0.3 m
Problem 1
Δtf = Kfm
X = (-1.86
○C/m)(0.3
X = -0.6
○C
m)
Colligative Sample Problem 2
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A water solution containing
an unknown quantity of
solute is found to have a
freezing point of -0.23 ○C.
What is the molal
concentration of the
solution?
Problem 2
Δtf = Kfm
 Δtf
Kf
= -0.23○C – 0○C = -0.23○C
= -1.86
m = x
○C/m
(packet)
Problem 2
Δtf = Kfm
-0.23○C = -1.86○C/m(x)
-0.23○C
=x
-1.86○C/m
X = 0.12 m
Colligative Sample Problem 3
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What is the boiling-point
elevation of a solution
made from 20.0 g of a
solute and 400 g of
water? The molar mass
of the solute is 62.0 g.
Problem 3
Δtb = Kbm
 Δtb
Kb
m
=x
=
○
0.51 C/m
(packet)
= moles solute/kg solvent
Problem 3
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Need to find moles solute:
20.0 g x 1 mole = 0.323 moles
62 g
m = 0.323 moles/0.4 kg
 m = 0.8
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Problem 3
Δtb = Kbm
 Δtb
Kb
=x
○
0.51 C/m
=
m = 0.8
(packet)
Problem 3
Δtb = Kbm
X=
○
(0.51 C/m)(0.8
X = 0.4
○C
m)
Homework
Complete
the
Colligative
Properties WS for
homework!
Lets do 6a together
LAB TIME!
Complete
the Freezing
Point
Depression
Lab.
Wrap Up
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Clicker Review
Today…
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Turn in:
 Get WS #2 out to check
Our Plan:
 Quiz, Quiz Trade
 Molality Quiz
 Colligative Lab
 Salting Roads Reading
 Test Review
Homework (Write in Planner):
 Test Review due next class
 TEST NEXT CLASS
Review Answers
V1
V2
V3
V4
#1
15.3 m
7.35 m
250.0 m
24.4 m
#2
-0.033 °C
-0.925 °C
-0.895 °C
-1.66 °C
Wrap Up
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Clicker Review #3
Clicker Review #4
Today…
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Turn in:
 Get out Test Review to Check
Our Plan:
 Worksheet Race
 Go over Test Review
 Unit 10 Test
Homework (Write in Planner):