Wednesday, January 16, 2013

Activity 8



Build a Molecule
Grade 4
Science Standards
 

  1. A.4.1 When conducting science investigations, ask and answer questions that will help decide the general areas of science being addressed.
  2. C.4.5 Use data they have collected to develop explanations and answer generated by investigations.
  3. C.4.6 Communicate the results of their investigations in ways their audiences will understand by using charts, graphs, drawings, written descriptions, and various other means, to display their answers.


Literacy Standards
  1.    C.4.1 Orally communicate information, opinions, and ideas effectively to different audiences for a variety of purposes.
  2.    C.4.2 Listen to and comprehend oral communications.

Directions:
-       1. Go through each molecule and put together the correct number of atoms to create the molecule. http://phet.colorado.edu/en/simulation/build-a-molecule
-      go through at least three collections.


-        After each collection draw a picture of the molecule created.
-      2. Choose one molecule from each collection and do some research to find what that molecule is a part of.
-       3. Once the three collections are finished go to the Large Molecules tab and create three different molecules that you remember putting together in the previous collections
-       4. The final step to the project, explain one of the molecules you created on your own and what atoms they contain.
-      5. When each of the classmates presents their findings, write down at least three different molecules that you didn’t create.





 The worksheet I created for this activity below.



Build a Molecule
   1.     Name the molecule and put the information into the chart.
Collection 1
Name Of Molecule
Name Atoms in the molecule
Drawing of the molecule






















Collection 2
Name Of Molecule
Name Atoms in the molecule
Drawing of the molecule























Collection 3
Name Of Molecule
Name atoms in the molecule.
Drawing of the molecule.






















   2.    Choose 1 molecule from each collection, search the internet and find what the molecule is used for.
Name of molecule
Use of molecule
Collection 1:

Collection 2:

Collection 3:



  3.    Write down in the chart the three molecules you’ve created from the large molecule part on the simulation.
Molecule 1:______________________________________________________
Molecule 2:______________________________________________________
Molecule 3:______________________________________________________


  4.    Explain one of the molecules you created on your own and what atoms they contain.___________________________________________________ _________________________________________________________
_________________________________________________________
    __________________________________________________________

  5.    Write down three molecules that you did not create, that your classmates created.

Molecule 1:_____________________________________________________
Molecule 2:_____________________________________________________
Molecule  3:___________________________________________________________

Activity 7



  1.     The color of the solution identifies if it is an acid, base, or neutral solution?
Answer:  B. False
  2.    Which solution is basic?
Answer:  D. More than one, because any solution that has a pH balance above 7.0 is basic.
  3.    Which solution is acidic?
Answer:  C
  4.    Which solution is basic?
Answer:  B
  5.    Which solution is acidic?
Answer: D both A and B are acidic
  6.    How will adding water affect the pH?
Answer: A. adding more water increases the pH.
  7.    How will equal amount of water affect the pH?
Answer: B.  decreases the pH.
  8.    What is the order from most acidic to most basic?
Answer: A; ABC
  9.    What is the order from most acidic to most basic?
Answer: C; BAC
  10.  If spit has a pH= 7.4, what does that tell you about the water equilibrium?  2H2O  OH-  + H3O+
Answer: A. something was added that made the equilibrium shift left.
Name: Larissa Lewan
Introduction to Strong and Weak Acids and Bases PhETLab(rvsd5/2011)
        How does the strength of an acid or base affect conductivity?pH?
Introduction:
When you test your pool’s pH, what are you those little vials or paper strips telling you?  When you hear an acid called “strong” or “weak”, what do those terms refer to?  In aqueous solutions, compounds can exist as molecules (undissociated) or ions (dissociated).  When an acid or a base exists in solution nearly completely as dissociated ions, we refer to that acid or base as strong.  A weak acid or base will donate ions to the solution, but will remain primarily as undissociated molecules.

Notation:
Acids are abbreviated HA, with the H representing the proton (H+) the acid donates to the solution.  The A is referred to as the acidic anion (A-) that is left in solution as the proton is donated.
Strong Bases are abbreviated MOH, with the OH representing the hydroxide ion (OH-) the base donates to the solution.  The M is cation (M+) that is left in solution as the hydroxide is donated..

Autoionization:
Even without any acid or base added a very small number of water molecules will form protons (H+) and hydroxide ions (OH-).  The protons will then form hydronium ions, the acid ion.

Procedure:PhET Simulations à Play With Sims à ChemistryàAcid-Base Solutionsà
The concentration of the acids and bases used in the  at 0.010 (10-2) Molar.

·         Begin with a strong acid and lower the pH probe into the beaker.  What is the pH of this solution? The pH is 2.00.
·         Test this strong acid with both pH paper and the conductivity probe.  What color does the pH indicator become?With the pH paper is it a 2.  Is this strong acid an electrolyte? yes  Does current travel through this solution? Yes it does.
·         Repeat the above tests with the weak acid, the strong base, and the weak base, and water.  Collect your observations in the table below:


Strong Acid
Weak Acid
Strong Base
Weak Base
Water
pH meter read
(value)
2.00
4.50
12.00
9.50
7.00
pH paper
(color)
Red
Orange
Blue
Green
Yellow
Conductivity
(bright/dim/none)
Bright
Dim
Bright
Dim
Very dim
Exists as Mostly
(ions/molecules)
Molecule
Molecules
Ions
Ions
Molecules
Procedure:
This simulation allows you to change the concentration of a strong and weak acid and base.
Complete the table below for some strong acids and bases and weak acids and bases by adjusting the concentration.
Strong Acids
Strength
Initial Acid Concentration (mol/L)
[HA] (mol/L)
[A-] (mol/L)
[H+] (mol/L)
pH
.010 M
Negligible
9.84 x 10^-3
9.84 x 10^-3
2.01
.050 M
Negligible
4.95 x 10^-2
4.95 x 10^-2
1.31
.100 M
Negligible
1.00 x 10^-1
1.00 x 10^-1
1.00
1.00 M
Negligible
1.00 x 10^0
1.00 x 10^0
0.00
Weak Acids
Strength(approximately)
Initial Acid Concentration (mol/L)
[HA] (mol/L)
[A-] (mol/L)
[H+] (mol/L)
pH
.015 M
1.50 x 10^-2
 2.39 x 10^-5
4.38
.150 M
1.50 x 10^-1
7.55 x 10^-1
7.55 x 10^-1
3.88
.015 M
2.33 x 10^-4
1.48 x 10 ^-2
1.48 x 10 ^-2
1.83
.150 M
1.85 x10^-2
1.32 x 10^-1
1.32 x 10^-1
.88
Strong Bases
Strength
Initial Acid Concentration (mol/L)
[MOH] (mol/L)
[M+] (mol/L)
[OH-] (mol/L)
pH
.010 M
Negligible
9.84 x 10^-3
9.84 x 10^-3
11.99
.050 M
Negligible
5.00 x 10^-2
5.00 x 10^-2
12.70
.100 M
Negligible
1.00 x 10^-1
1.00 x 10^-1
13.00
1.00 M
Negligible
1.00 x 10^0
1.00 x 10^0
14.00
Weak Bases
Strength(approximately)
Initial Acid Concentration (mol/L)
[B] (mol/L)
[BH+] (mol/L)
[OH-] (mol/L)
pH
.015 M
1.50 x 10^-2
7.90 x 10^-6
7.90 x 10^-6
8.90
.150 M
1.50 x 10^-1
2.50 x 10^-5
2.50 x 10^-5
9.40
.015 M
2.33 x 10-4
1.48 x 10^-2
1.48 x 10^-2
12.17
.150 M
1.85 x 10 ^-2
1.32 x 10^-1
1.32 x 10^-1
13.13
Conclusion Questions:
1.       A strong acid is very concentrated / exists primarily as ions. (circle)
2.       A weak base is a nonelectrolyte / weak electrolyte / strong electrolyte.
3.       A strong base is a nonelectrolyte / weak electrolyte / strong electrolyte.
4.       At the same concentration (Molarity) a strong acid will have a higher / lower / the same pH as a weak acid.
5.       As concentration of a weak acid increases, the pH increases / decreases / remains constant.
6.       As concentration of a weak base increases, the pH increases / decreases / remains constant.
7.       As the concentration of a weak acid increases, the number of ionsincreases / decreases / remains constant.
8.       As the concentration of a weak acid increases, conductivityincreases / decreases / remains constant.
9.       As the strength of a weak acid increases, the proportionof ions to moleculesincreases / decreases.
10.   As the strength of a weak acid increases, the conductivityincreases / decreases / remains constant.
11.   What are the pH values of a weak acid with a concentration of 0.10 and a strong acid with a concentration of 0.01, ten times lower?              Weak acid, 0.10 M : 4      Strong Acid, 0.01 M   2    
12.   Explain the significance of the results of your calculation above. The strong acid is two times less then the weak acid.