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  Q1 : Week 11  – 11/7 – 11/12

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 11/7 – Monday – B Day – 2, 3a Lab/4                                         Jump to:  Monday Homework

 Main focus –                                                                                                                                                         
                                                    

a) To begin our discussion of acid/base chemistry –

b) To identify strong acids, weak acids, strong bases, and weak bases and relate these strengths with Coulombs Law

c) Introduce Keq or Ka values as a quantitative value of the strength of acids.

 Period 2: 

1.  Test 2 – give back- more detailed review tomorrow.

2.  Acid/Basics intro lesson – We will continue our tour of Stoichiometry through acid/base chemistry  

                                                                                                                

Period 3/4: 

1.  Test 2 – give back- more detailed review tomorrow.

2.  Acid/Basics intro lesson – We will continue our tour of Stoichiometry through acid/base chemistry  

3.  Acid base / electrolyte lesson.                                                                                                             

                                                                                                                    

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ACID and Base NOTES:

Acid/Base basics (no pun intended…ok maybe) – Stoichiometry through Acid/Base reactions.
 
 Demos – magnesium hydroxide, electrolyte 
                              a) Strong Bases – weak bases Table F
                                   Coulombs Law!
 
                              b) Acid and base definition introduction
                                      Why acids are dangerous? – what is the action of H+
                                      Why bases are dangerous?  – What is the action of OH–
                                       Neutralization reaction –  example :  OH- from Mg(OH)2
                               c) Conductivity of metals – mobile electrons
 
                               d) Electrolyte definitions – mobile ions
                                      Strong ACids and Bases are strongest electrolytes
                                      Salts that are soluble are electrolytes in (aq) and (l) phases only
                                      Stiochiometry is with Strong Acids or Strong Bases – (completion reactions)
                                      Weak acids/Weak bases do not completely dissociate.
                                       Vinegar (organic acid) weak acid = structure
 
                                e)   Strong Acids – from Halogens – why HF is weak and why HCl, HBr, HI are strong?
                                                Coulombs LAW!!!!       
 
                                        Milk of Magnesia = Mg(OH)2                                                                   Drano = NaOH
Both produce OH- ions but one is dangerous why?
                  NaCl (s)

 Ionic solids  – NOT Electrolytes!

(positive and negative ions locked in a crystal)

  They are never electrolytes because the do not conduct electricity in solution or as a  liquid.  The ions ARE NOT FREE and thus cannot move.  It is the movement of ions that will enable them to conduct a charge.  All ionic compounds are a solid at STP due to STRONG COULOMBIC Attractions between the positive and negative ions.  Each ion is actually surrounded by 6 other oppositely charged ions that keep the ions in a very stable (low energy) structure.

THUS IONIC Compounds in a solid state NEVER conduct a charge!

  Ionic liquids – Electrolytes

 These liquids require very high temperatures to occur as the ions would want to attract to each to form a crystal at lower temperature BUT at these high temperatures these liquids (of negative and positive ions) can conduct because the ions are free to move!
               NaCl (s)     —–>      Na+(aq) + Cl– (aq)

 Ionic solutions –  Electrolytes
(dissolved ions) – must be soluble! 

 

 

These solutions ARE electrolytes!  The ions although surrounded by water, are free to move and thus charge can be conducted through. the solution.

IF the ionic solid is insoluble then it will not make a solution and the ions will still be locked in a crystal which will result in no charge being conduced         
                                Sucrose (s)

 Molecular compounds – NOT Electrolytes!

Make molecules not ionic crystals

These are made from nonmetals (small atoms) with a high attraction for electrons. These compounds make bonds by fighting for electrons between atoms since they all have high attraction for electrons. Each bond — is a pair of electrons between these atoms.  Because of the “tug of war” for electrons between these compounds, these electrons are not free to move and conduct a charge.  In fact because the electrons are held so tightly these compounds are so poor at conducting we call them insulators.

Molecular compounds NEVER conduct as a solid or in a solution (even if they dissolve).
Molecule compounds NEVER conduct in a solution because they are molecule with NO charge and thus are not electrolytes!
Even if they are dissolved in solution there are no ions as theses are only atoms (Neutral!)
             Metallic compounds – Fe (s)

   Metallic compounds  – NOT electrolytes

 These compounds do conduct in the solid state because they are made of metals (large atoms with a low attraction for their electrons) and thus allow the electrons in their outer most shell to “roam” throughout the crystal.  They unlike molecular compounds have loosely held electrons and thus these electrons are allowed to move freely.  Free moving charges conduct electricity!!

We say that metallic compounds have a sea of mobile electrons in a crystal of positive nuclei.  Do not confuse the positive circles with ions as they are the nuclei of the atoms.
So electrolytes are compounds that conduct electricity as FREE IONS!
 
                    a) IONIC compounds (salts) that are melted (molten)
                b) IONIC compounds (salts) that are dissolved
                c) Base solutions – FREE OH–  ions
             d) Acid solutions – Free H+  ions
 
NOT Electrolytes: 
 
                a) Ionic solids in the solid phase 
                b) Molecular compounds
                c) Metallic compounds
 

Acid/Base Intro Presentation:

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11/7 – Monday’s Homework: – 

1.  Please continue our acid base intro with the lecture 2 video below IF you need a refresher on today’s intro acid and base lesson.

2. Complete the form below on today’s concepts.You will have 3 graded submissions. 

3. Review your test with the key below to figure out why you were incorrect in your responses and if  I did not give you credit for something you got correct. I do make mistakes, I am tall.

Key to TEST 2  

LAB 7 – formal write-up is due Friday!!! I will go over the conclusion at some point in class this week

 

1 : Acid Base Intro 1 lesson:

 

1 : Acid Base Intro 2 lesson:

 

 2: Acid base intro Lesson Form: Check #7 from key for next year!

 

Electrolytes Demo (Ernie!):

 

Milk of Magnesia Demo (Weak Base = insoluble salt with a hydroxide):

 End of Monday

_______________________________________________________________                                                         Jump to:  Tuesday Homework

11/8 – Tuesday – A Day – 2/3a Lab, 4                                            

Main focus –                                                                                                                                                         

                                                   

a) To review concepts of an electrolyte with acid and bases and their relative strengths.

b) To define and review the ACID /Base guys (theories that define acids and bases)..

 

Period 2/3a –  

1.   A quick review of the electrolyte concepts (free ions), strong and weak base and acid.

Electrolytes allow charge to flow through solutions. They are important in voltaic and electrolytic cells. OUR Nervous system requires electrolytes to conduct an action potential. Our heart creates its own beat by creating a voltage by the movement of ions (sodium/potassium pump)!

       a) Conductivity demo with

        metals – metallic solids – sea of mobile electrons

        dry salt – Ionic Solid – ions locked in a crystal lattice

        dissolved salt – Ionic solution –  ions that are free to move throughout the solution with water

        dry sugar – Molecular solid – molecules held togther by intermolecular forces

,       dissolved sugar – Molecular Solution – polar molecules dissolved in water (polar solvent)

        vinegar – weak acid – a solution of ions from incomplete dissociation of  acid weak acid into free ions

         HCl – strong Acid –  a solution of ions from the complete dissociation of acid into free ions.

         Mg(OH2) – weak base –  a solution of a weak base from incomplete dissociation of the base into ions

         NaOH – Strong Base – a solution of a strong base from complete dissociation of the base into ions.

2.   Acid/Base definitions – beginning of the acid/base packet     

Classwork:
Acid and Bases Intro packet new.pdf
View Download  

3.   Weak acid/base equilibria, Conjugate acid, Conjugate base                                                                                       

Period 3/4: – 

1.   A quick review of the electrolyte concepts (free ions), strong and weak base and acid.

2.   Acid/Base definitions – beginning of the acid/base packet       

3.   Weak acid/base equilibria, Conjugate acid, Conjugate base     

 

                                                             

Today’s lecture:

 

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11/8 – Tuesday’s Homework: – Please refresh as this will change based on how far we get in class

 

1.  View lecture below (start at 14:40 to 37:50) and Complete Page 2 of the Acid base Intro Packet  and review with the key below (after watching the video): Please skip the Lewis Acid/base definition explanation. I will review that tomorrow in class!

Acid and Bases Intro packet new.pdf
View Download
 
Intro Acid Bases Packet Key 1718 p.pdf
View Download
 
2. NOW complete the all three of reactions (or the 2 remaining) on the Conjugate Acid Base Pairs and Complex ions new.pdf 
 and review with the key below:
 
Conjugate Acid Base Pairs and Complex ions new.pdf 
 
Conjugate Acid Base Pairs and Complex ions new key p.pdf
View Download

                                            

So everyone should have the first 2 pages of the packet completed (excluding the Lewis definition on front page) AND should have the Conjugate Acid Base Pairs worksheet completed (front side).   

                               

Page 2 video for homework starting at 14:40:

End of Tuesday!

  _________________________________________________________________________                                  Jump to:  Wednesday Homework

11/9 – Wednesday – B Day – 2, 3a Lab/4                                

Main focus –          

    a) To define Lewis acid/base definition and weak acid /base equilibria

     b) To introduce the auto – ionization of water, pH, pOH, Kw, -log, 10-x

 

Period 2 –                

1.  Complete the Lewis acid/base definition in explaining the CO2. 

2.  Review weak acid/base equilibria

Conjugate Acid Base Pairs and Complex ions new key p.pdf
View Download

3.  Auto- Ionization of water lesson:     

        a) Demo – pH probe demo with straw and washing soda
                            Pictures of the pool chemicals
                             copper ions pH probe

   

Period 3b, 4 –        

1.  Complete the Lewis acid/base definition in explaining the CO2. 

2.  Review weak acid/base equilibria

Conjugate Acid Base Pairs and Complex ions new key p.pdf
View Download

3.  Auto- Ionization of water lesson:     

        a) Demo – pH probe demo with straw and washing soda
                            Pictures of the pool chemicals
                             copper ions pH probe

       

         b) Started Pages 3 and 4 of the intro packet.

 

 
                                                                                                                       

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ACID and Base NOTES – Lewis Acid mechanism of Carbon Dioxide

This is the mechanism of how CO2 acts an acid by the the Lewis Definition.

The most complete definition is the Lewis acid base definition because there are acids and bases that DO NOT HAVE protons to donate or possibly accept BUT create acidic conditions or Basic Conditions.
 
In table K they list CO2 an acid but it had no protons to donate?  It is an acid because when we bubble CO2 in water the conditions in water become more acidic.  
 
                    CO2  +   H2O             ——>              intermediate                  ——>             H2CO3
                                                                                                                                                                                      then…..
                                      H2CO3   +   H2O  <——>  H3O+  +   HCO3 -1
 
CO2 can accept a pair if electrons (JUST LIKE a proton!!!) so the best and most complete definition of acids and bases is the LEWIS acid base definitions! Lewis acids like CO2 are electron acceptors while bases like water in the example are electron donators!!
 
Demo with straw and pH probe.

CO2 acts an acid by the the Lewis Definition.

The most complete definition is the Lewis acid base definition because there are acids and bases that DO NOT HAVE protons to donate or possibly accept BUT create acidic conditions or Basic Conditions.
 
In table K they list CO2 an acid but it had no protons to donate?  It is an acid because when we bubble CO2 in water the conditions in water become more acidic.  
Back to the pumpkin Stoichiometry from last week:

C2H2 (g)  +   5/2O2 (g)    —> 2CO2 (g)   +  H2O (g)

                                                                
                                             0r
 
2C2H2 (g)  +    5 O2 (g)    —> 4CO2 (g)   +  2H2O (g)
The chemical reaction that exploded the pumpkin was combustion or redox but the reaction the made fuel, C2H2 was?   What kind reaction is this?
 

                       CaC2 (s)   +   2H2O (l)           —–>                C2H2 (g)    +    Ca(OH)2

The Arrhenius definition although a good start to defining acids and bases is not complete because we have chemicals that do not have any hydroxide ions in their structure (like NaOH) but will create acidic or basic conditions in water.  In the case above,  the hydroxide ion (OH–) was produced by the action of the  carbide ion (C2-2).   So the Bronsted-Lowry definition is a more complete definition because it includes those chemical species that Produce the Basic or Acidic conditions by Accepting a proton or donating a proton.                                                                                                                                                                                     
In the case above the carbide ion (C2-2) ion is the Bronsted-Lowry base (the carbide ion accepted the proton.) and the water is the Bronsted- Lowry acid (because water DONATED A PROTON) (
 
*Notice that acids must have electron deficient hydrogen to donate protons (H+).
 *Notice that Bases must have an ability to accept protons (H+).  Having a lone pair of electrons or having a negative  charge helps attract the protons!
 
 The result of this acid base reaction is that acetylene C2H2 was produced.
 
 

:        _________________________________________________

ACID and Base NOTES – Auto Ionization of water = pH concepts

*Connections–   Stoichiometry (mole ratio) continues with Acid/Base Reactions.  The connection we need to make is that salts that are soluble and that produce a hydroxide ion (OH–) into an aqueous solution are bases.  These are important ions because they can upset the balance of H+ and  OH– in water.  Remember that these are naturally occurring ions that occur in water.  
This called auto-ionization of water.
 
                                           H2O (l)  →     H+ (aq)       +     OH– (aq)             Kw =  1 x 10-14
                                                             Proton                   Hydroxide
 
                                                                              or
 
                        H2O (l)  +  H2O (l)  →    H3O+ (aq)    +   OH– (aq)              Kw =  1 x 10-14
                                                             Hydronium         Hydroxide
                                 
                                            From 2 reactions above which are really the same you
                                               can see ONE H+ or H3O+ for every ONE OH–.
 
                                              1  H+ / H3O+    :   1 OH–
 
Acids will increase the H+ or the  H3O+ concentration above normal* conditions.
 
                               Bases will increase the OH– concentration above normal* conditions.
 
*Normal conditions refer to water that is NEUTRAL : (  H+ or the  H3O+ =   OH– )  = pH = 7
 
                                                   H2O (l)  →    H+ (aq)        +   OH– (aq)                                                                   
                                H2O (l)  +  H2O (l)  →    H3O+ (aq)   +   OH– (aq)   
 
                                        Keq =   [Products]   =  Kw = [H+ / H3O+][OH–]
                                                     [Reactants]
 
*We can use H3O+ and H+ interchangeably.  I will write H+ going forward but remember I can use H3O+ at any time and it would mean the same thing.  (Whether you have a free proton or a a proton held by water does not matter)
 
The value of Kw (equilibrium constant for the auto-ionization of water) equals =  Kw = 1 x 10-14
                                                                                      
                                                       Kw = [ H+ ]    x     [ OH–]                                                                                                                                 
                                           1 x 10-14   = [ H+]     x    [ OH–]
 
If one H+ dissociates for every ONE OH– :  H2O (l)  →    H+ (aq)        +   OH– (aq)    then:                                
                                           1 x 10-14   =  [ H+]     x    [ OH–]                                                                                                                                                                             
                                          1 x 10-14    =  [1 x 10-7]     x    [1 x 10-7 ]                                           
                
As you can see the concentration (molarity, M) of H+ and  OH–  ARE THE SAME IN PURE WATER! 
                                                       
They must be the same concentration to equal 1 x 10-14 !
*Remember when you multiply exponents you add!
 
*THIS is WATER AT NORMAL CONDITIONS.                           
 
 Now we use a convention to measure this balance or unbalance of ions in water.  It is called pH.
 
                                     pH = – log (base 10) of the H+ or  H3O+ concentration.
 
                            Pure water at 4 degrees Celsius the [H+] or  [H3O+]  = 1 x 10-7
                            if you put  -log (1 x 10-7) in your calculator you will get :  pH  = 7
 
So basically pH is a numerical system that  “stuffs” the entire concentration (small value) into a exponent (base 10) AND MAKES IT positive for Ease  
 
                                                                            pH = – log  [H+]  
 
a)What if the [H+] = 1 x 10-5  ?  What is the pH?   Is this an acid, basic or neutral solution?
 
b)What if the [H+] = 0.001  ?  What is the pH?  Is this an acid, basic or neutral solution?
 
c)What if we have a [HCl] = 0.1 M   What is the pH?  Is this an acid, basic or neutral solution?
 
d)What if we have a [HCl] = 5.6 x 10-6   What is the pH?  Is this an acid, basic or neutral solution?
 
e)What if you have [NaOH] = 0.001    What is the pH?  Is this an acid, basic or neutral solution?                                                                 
e)What if you have [NaOH] = 3.34 x 10-5   What is the pH?  Is this an acid, basic or neutral solution?
 
*Notice the above problems are strong Acids and Base, which means complete dissociation.
 
 answers on bottom of today’s homework post..   
 

Auto-ionization of water lesson – today’s Lecture and also part of the packet questions reviewed.

 

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11/9 – Wednesday Homework: –

There is a small amount of homework tonight!

 

                                                                                                                                        There is no homework today!

Answers for question in notes above.

a) pH = 5   Acidic solution (below 7)
b) pH = 3   Acidic solution (below 7)
c) pH = 1    Acidic solution (below 7)
d) pH = 5.25  Acidic solution (below 7)
e) pOH = 3  thus  pH = 14 – 3 =  pH = 11  Basic solution (above 7 – more OH– than H+)
f) pOH = 4.48  thus pH = 14 – 4.48 = 9.52  Basic solution (above 7 – more OH– than H+)

                                                                                                                                                                                                                                  Jump to:  Thursday Homework
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11/10 – Thursday – A Day – 2/3a Lab, 4                                                                                                               

Main focus –     
                                                                                                                                               

a) To calculate the hydronium or hydroxide concentration from pH.

b) To calculate the pH of a strong acid or strong base from its molarity.

c) To identify an acid/base indicator as a conjugate acid /base pair.

 

Classwork: (pages 3 and 4)

Acid and Bases Intro packet new.pdf
View Download
 
Intro Acid Bases Packet Key 1718 p.pdf
View Download                                                                                                                                                           

Period 2/3 – Conclusion discussion of Lab 7

1.  A quick Review of the Table of Ka’s,

     Lewis acid/base definition – Pumpkin Stoichiometry connections

       a) Complex ions – backside of the conjugate acid worksheet – COULOMBS LAW!!!!!!!

Conjugate Acid Base Pairs and Complex ions new key p.pdf
View Download

2.  Complete the pH, pOH, pKa lesson. Started yesterday – Notes posted yesterday.

a) complete page 3 of the packet.

 b) washing soda demo/ straw – connect the carbonate ion to basicity – (pH probe demo)

c) Introduce the idea that there are basic, neutral, and acidic salts.

3.  Chemical indicators – structure and function – Table M – Presentation

        a) Page 4 of the packet
        b) straw and bromothymol blue demo
        c) phenolphthalein – rough titration.

 

Period 4 – Conclusion discussion for Lab 7

1.  A quick Review of the Table of Ka’s,

     Lewis acid/base definition – Pumpkin Stoichiometry connections

       a) Complex ions – backside of the conjugate acid worksheet – COULOMBS LAW!!!!!!!

2.  Started with page 3, last question to complete to review the pH, pOH, pKa lesson.

3.  Washing Soda – or pH up pool chemicals   

4.  Chemical indicators – structure and function – Table M – Presentation 

        a) Page 4 of the packet
        b) straw and bromothymol blue demo
        c) phenolphthalein – rough titration.

 

 

                                                                                                 

:        _________________________________________________

ACID and Base NOTES – Acidic, Basic, or Neutral salts

Notes for acid/ base salts:

Ionic compounds will dissociate into their cations (+) and anions (-) IF THEY ARE SOLUBLE and when they do they can act as either a base or an acid (or not react at all) in water.  If the ions of the salt act as an acid or base they can ionize water as either a hydronium ion (H3O+) or as a hydroxide ion (OH–) by following our acid/base definitions. 

For example if we have the following soluble salt:  NH4Cl

                                                                    NH4Cl    —->     NH4+   +     Cl–

NH4+WILL IONIZE Water :

                                                       NH4+  +   H2O    —->    H3O+ +   NH3

Since we are increasing the hydronium ion the pH drops and ammonium chloride is an acidic salt.

For example if we have the following soluble salt:  Na2CO3

                                                               Na2CO3     —->   2Na+   +   CO3-2

CO3-2 will ionize water:

                                                      CO3-2  +   H2O    —-> HCO3-1   +   OH–

Since we are increasing the hydroxide ion the pH increases and sodium carbonate is Basic salt!

What about these expensive pool chemicals????

Here are some expensive pool chemicals that change the pH.
 
If the pH is not optimum (about 7.4) then the disinfectant (chlorine) will not work and the liner, metals (on heater), or grout (in stone pools) will decompose.
                             Na2CO3                                                                                                NaHSO3
                                           Washing soda                                                                                             Toilet bowl cleaner/fungicide

 

                          Basic Salt                                                                          Acidic Salt

Acid Base Indicators Presentation:

Today’s lesson – today’s Lecture 

 

______________________

11/10 – Thursday Homework: – 

* Test 3 will will be Monday/Tuesday next week  (it will count twice) and it will be everything we have done in the new ACID/BASE area. 

1.  Lab 7 – Formal Lab is due Saturday 11/12.  I need to grade it for quarter 1. You should only have the conclusion left. If the conclusion is a problem please email your questions.

The lab requirements including what is responsible in the conclusion is posted in week 9 (very bottom of page).

2. The last concept that we did not complete in our acid base packet is the concept of acid base indicators.  These are chemicals that change their molecular structure in the presence of acidic or basic solution. Their molecular structure changes in a way that allows the chemical to absorb different parts of the visible spectrum and thus change colors. There color changes can be used to identify acids, bases, and when neutralization occurs.

a)  Please view Today’s lecture (above) from 33:00 till the endand complete page 4 of the acid base packet. We skipped the acid/base indicators questions. Answer those questions and review with the key below.

Intro Acid Bases Packet Key 1718 p.pdf
View Download   

b) Please view the Lewis Acid Carbon Dioxide Demo below.

3.  Please complete the  SIDE 1 –  Stoichiometry 5a – Acid Base Reactions new.pdf worksheet with using the posted video below.  

 
This is a lesson in writing Net Ion Acid/Base Reactions!
 
*Remember that soluble salts (aq) were never written together in NET ION EQUATIONS while the precipitate (s) are because they do exist in a crystal together.  In Acid/Base the “soluble ” compound is the “Strong” Acid or Base because they completely dissociate just like soluble salts, however weak acids and bases are NOT completely dissociated thus must be written together. WATER IS A NEVER Written dissociated because they barely dissociate!!!
 
Stoichiometry 5a – Acid Base Reactions new.pdf
View Download 
 
Stoichiometry 5a – Acid Base Reactions new Key.pdf
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4.  Please complete side 2 of the Stiochiometry 5a – Acid Base Reactions new.pdf with me in the 2nd video below:

Side 2 is about stoichiometry problems using acid base chemistry.  

5.  Please complete the Acid Base Intro Form 2 based on the packet. You have 4 submissions to this form. Your Test 3 is based on this material. Please complete this AFTER you completed Stoichiometry 5a worksheet.

 

2: Lewis Acid Carbon Dioxide Demo 

3: Tutorial on Stoichiometry 5a – Acid Base Reactions new.pdf worksheets:
New Side One Lecture : Acid/Base Net Ion Reaction Review:                                                                                                                                         
Okay i made an error on the last net ion reaction. The product of NH3 and H3O+ is NH4+ and water (H2O)! Sorry about that! I was trying to illustrate the reaction between a Strong Acid (H3O+) and a weak base (NH3) thus water would be made in the neutralization reaction. (Thanks Josh Kaplan 2018)                                                                                                                                             

 

4: Tutorial on Stoichiometry 5a SIDE 2: acid base stoichiometry problems! 

 

 

 5: Acid base intro Lesson Form 2: 
   

 

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11/11 – Friday – Veterans Day – OFF – enjoy! 

 
End of Quarter 1!