unit 13 acids and bases - katy independent school...
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Unit 13
Acids and Bases
Name: ___________________________ Period: ______ TEST: Wednesday 4/27/16
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Unit 13 – Acids and Bases – Calendar
Monday Tuesday Wednesday Thursday Friday
APRIL 7th
Solutions
Test
8th
Video: Acids & Bases
Notes #1
Acids and Bases
Characteristics and
Arrhenius and Bronsted
Lowry definitions
HW: Pg. 6
11
Notes: pH scale:
HW: Pg. 9
12
Go over Gas Law,
Bonding, and
Solutions Tests
HW: Study for
Cumulative Exam
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Cumulative
TEST
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pH and pOH
calculations -
Math Practice
HW: Pg 12
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Quiz?!?!?!
Crossword puzzle
Pg 13-14
Half day
End of 5th six weeks
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PHET Computer Lab
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Neutralization and
Titration Notes
HW: Pg 17
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Titrations – Pre Lab
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Titrations
HW: Study Guide
Pg 18-21
22 Titrations
HW: Study Guide
Pg 18-21
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Alien Juice Bar
Computer Lab
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STUDY GUIDE
DUE!
Review
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Acids &
Bases
TEST
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Notes #1: Introduction to Acids and Bases
Acid: ____________________________________________________________________________
Properties of Acids:
o ______________________________ (lemon juice)
o ___________________
o Both strong and weak
o Will cause indicators to change colors
o A metal + an acid will produce ___________________
o
o
o
o Single replacement reaction
Acid + Metal → ____________________ + a “__________”
o Double replacement reaction
Acid + Base → ___________ + a “__________”
Examples: HCl, soda, coffee
Naming Rules:
ION TYPE ION ENDING ACID NAME BEGINNING ACID ENDING
Polyatomic
-ite NO hydro- beginning -ous
-ate NO hydro- beginning -ic
Monatomic -ide hydro- beginning -ic
EX: Examples of Naming Binary Acids
• HCl
• HF
• HBr
EX: Examples of Naming Ternary Acids
• H2SO4 Sulfate is the poly, so __________________________________
• H2CO3 Carbonate is the poly, so ________________________________________________
• H2NO2 Nitrite is the poly, so __________________________________
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Base: _____________________________________________________________________________
Properties of Bases:
o ___________________
o ___________________ (soap)
o ___________________
o Both strong and weak
o Will cause an indicator to ___________________ colors
o
o
Examples: NaOH, soap, antacids, drano, bleach
Naming Bases
• The easiest are the bases, since most of these are ______________ hydroxides,
compounds you already know how to name.
• Metal hydroxides are named in the same way any other ionic compound is
named. First give the name of the __________________ ion. Follow this with
the name of the anion, which, in the case of bases, is “____________________”.
• KOH –
• Mg(OH)2 -
Other definitions of Acids and Bases
Arrhenius Acids and Bases:
o Acid: _______________________________________________________________________________.
o Base: _______________________________________________________________________________.
Brønsted – Lowry Acids and Bases
o They felt the Arrhenius definition was too limiting.
o Acids: __________________________________________________________________________
Brønsted – Lowry Acids and Bases cont.
o Bases: _________________________________________________________________________
Ex: NH3 + H2O ↔ NH4+ + OH-
EX: HCl + H2O ↔ H3O + + Cl-
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Amphoteric: __________________________________________________________________
Strong Acids/Bases: ____________________________________________________________
o Ex: HCl, NaOH
Weak Acids/Bases: ____________________________________________________________
o Ex: NH3, Acetic Acid (vinegar)
o Tooth decay is caused by the weak acid – lactic acid: C3H6O3
Strong Electrolytes
breaks apart into its ions
Are conductors of
electricity
Will produce a ___ light bulb
Examples of Acids and Bases that are Strong Electrolytes:
Weak Electrolytes
breaks apart into its ions
Are conductors of
electricity
Will produce a _______ light bulb
Examples of Acids and Bases that are Weak Electrolytes:
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HOMEWORK – DAY 1 NOTES
Which picture at right is the:
1. Strong electrolyte ______
2. Weak electrolyte ______
A B
IDENTIFICATION - Identify the following examples as: A = acid B = base S = salt (neither acid not base) Remember from the previous units, a salt is any ionic compound, excluding what we classify as a base. ____1. AgOH ____2. MgSO4
____3. ZnCO3
____4. H2SO4
____5. NaOH ____6. HClO
____7. Mg(OH)2
____8. HNO3
____9. Pb(ClO)2
____10. (NH4)2CO3
____11. HC2H3O2
____12. HBr
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pH SCALE Notes: pH and pOH
MEASURING pH Scientists use a pH scale to measure the strength of an acid or base. The term pH stands for “potential for hydrogen”. The amount of hydrogen in a substance determines its acidity or alkalinity. Alkaline is another term for base. A number on the pH scale is used to describe the strength of acidity or alkalinity. The most commonly used pH scale goes from 1 (very acidic) to 14 ( very basic). The number 7 on a pH scale means neutral – neither acid nor base. The concentration of hydrogen ions in a solution is described by its number on the pH scale.
• A _____________pH tells you that the concentration of ____________________________ ion
is _____________. EX: pH 2
• By comparison, a ___________________ pH tells you that the concentration of
_________________________ ion is ___________________. EX: pH12
Self-ionization of water: _____________________________________________________________________________________
________________________________________________________________________________________________.
H2O + H2O OH- + H3O+
Also written as: H2O H+ + OH-
The H3O+ and H+ represent hydrogen ions in solution.
Neutral Solutions
In pure water, the concentration of hydrogen ions is ______________________to the concentration of
hydroxide ions
1 x 10-7 M or pH of ______ o (Remember that M is the unit for Molarity)
[H+] = [OH-] o (brackets represent concentration)
The represents a ________________ _________________________
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Solutions
In a solution, if the [H+] _______________________ the [OH-] _____________________ and vice
versa. o Think back to our see-saw. As one “person” goes up the other “person” goes down.
Ion-product constant of water, Kw:
Kw = [H+] x [OH-] = 1 x 10-14 M
Acidic Solution:
The [H+] is ____________________________than [OH-].
Therefore, the [H+] is ____________________________________________________
Basic Solution:
The is [H+] less than [OH-].
Therefore, the [H+] is ______________________________________________
A.k.a. ___________________________________________________________
Let’s review: Complete the chart below:
Type of Solution pH Ranges [H+] versus [OH-] Example
Acidic Neutral Basic or Alkaline
Acids Bases
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Homework:
1. Use the pH scale on page 7 to rank battery acid, vinegar, orange juice, milk, and bleach in
order of increasing acidity.
2. Complete each section:
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pH CALCULATIONS
pH = - log[H+]
pH [H+]
Kw = [H+] [OH-]
Remember: The pH scale ranges from 0-14
o 0 = ______________________
o 7 = ______________________
o 14 = ______________________
pH = ___________________________
What is the pH of a neutral solution?
o Calculate using the Logarithmic function on the calculator
( see photo to the right)
Sample Problems
As long as you have a ____ x 10 to some power, the pH is the exponent. If the number before the
“x10” is anything other than 1, you MUST use the formulas to find the pH.
1. What is the pH of the following concentrations?
a. [H+] = 1 x 10-2M =
b. [H+] = 1 x 10-9 M =
c. [H+] = 1 x 10-5 M =
2. What is the pH of the following concentrations? Use pH = - log[H+]
a. [H+] = 2 x 10-2M =
b. [H+] = 6 x 10-9 M =
c. [H+] = 3 x 10-5 M =
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Other Formulas and Problems
pH 14 = pH + pOH (See example 1 below)
Using the Equilibrium constant labeled as _______________
Kw is ________________________
Kw = __________________________
EX: What is the pH of a solution with a [OH-] of 4.0 x 10-11M?
Use Kw to find [H+] then find pH using –log function.
Example Problems
1. If pH = 5, pOH =
Is this solution acidic, basic or neutral?
2. What is the pH of a solution that has a hydrogen ion concentration of 1.0 x 10-5M?
Is this solution acidic, basic or neutral?
3. What is the hydrogen ion concentration of a solution with a pH of 11? Which has a greater concentration:
H+ or OH-?
4. A solution has a hydrogen ion concentration of 1.2x10-8M. Determine the pH of the solution. Is this solution
acidic, basic or neutral?
5. Assuming Kw = 1x10-14, calculate the molarity of OH- in solutions at 25ºC when the H+ concentration is
0.2M.
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Homework Practice Problems on pH
Solve the following problems. Be sure to show work for each problem.
1. Determine the pH of a solution that has a hydrogen ion concentration of 1.0x10-9M.
Is this solution acidic, basic, or neutral?
2. Lime juice has a hydrogen ion concentration of 1.3x10-2M, while the [H+] in lemon juice in 0.067M.
Calculate the pH for each juice.
pH of lemon =
pH of lime =
Which is more acidic?
3. What is the hydrogen ion concentration for a solution with a pH of 8?
What is the pOH of the solution?
4. Knowing Kw = 1x10-14, calculate the molarity of OH- in solutions at 25ºC when the H+
concentration is:
a. 5 x 10-10 M
b. 100 M
5. Determine the pH of a solution if the [OH−
] = 4.93 × 10−8 . (Hint: solve for [H+] using Kw, then pH)
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REVIEW OF ACID/BASE PROPERTIES AND ELECTROLYTES
WORD BANK
corrosive strong dim slippery below
bright neutral all above I Chemistry
acidic weak hydroxide hydronium metals
amphoteric acid(s) base(s) red blue
hydrogen bitter sour electrolyte basic
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Hints for the Crossword Puzzle
Across
4. able to act as an acid or base.
6. Bases have a taste.
9. solutions contain hydrogen and hydroxide ions.
10. Acids will react with to produce hydrogen gas.
14. Acids have a taste.
17. An acid or a base can be called a(n) because either can
conduct an electric current.
18. For a weak electrolyte, the light bulb will be .
19. the name of the ion commonly found in bases
20. A electrolyte will partially dissociate.
Down
1. A electrolyte will completely dissociate.
2. harmful, destructive, caustic
3. the type of solution that has a higher hydrogen ion concentration the hydroxide
ion concentration
4. Fruits and vinegar are examples of .
5. Bleach, ammonia, and soap are all examples of .
7. Bases feel .
8. For a strong electrolyte, the light bulb will be .
11. For bases, the pH is seven.
12. Bases turn litmus paper .
13. For acids, the pH is seven.
15. the color of pH paper in an acidic solution
16. the element commonly found in acids
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Neutralization Notes
Acid-Base reactions will produce _______________ ____________________ when completely
neutralized.
Salts are compounds consisting of a(n) ____________________ from an acid and a(n)
_______________ from a base.
In general, reactions in which an acid and a base react in an aqueous solution to produce a salt and
water is called Neutralization Reactions.
Neutralization occurs when an Acid + Base ↔ ______________ + __________
o Salt: Anion from acid and the cation from the base join together to form a salt.
Where do we see this process?
o _____________
o Farmers controlling the ___________ of soil
o Formation of ______________
A strong acid + a strong base = neutral solution
o Examples:
HCl + NaOH ↔ H2O + NaCl
HCl + KOH ↔ H2O + KCl
Practice: Don’t forget to balance them after you write them.
HCl + LiOH →
HNO3 + CsOH →
HBr + KOH →
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Titrations Titration:______________________________________________________________________________
______________________________________________________________________
o If you don’t know the concentration of one solution, you can figure it out by performing a
neutralization reaction, or titration, with a __________________ ______________________.
o A standard solution is one of ________________ ________________.
Performing Titrations
o Steps in a neutralization reaction:
A measured volume of an _______________ solution of ________________
concentration is added to a flask.
Several drops of ________ are added to the solution.
Measured volumes of a ________ with a ________ concentration are mixed into the acid
until it barely changes color.
o End Point: __________________________________________________________
Once you have reached the end point, you can perform calculations to find the unknown
solution.
3. Example: A 25 mL solution of H2SO4 is completely neutralized by 18 mL of 1.0 M NaOH. What is the
concentration of H2SO4 solution?
a. Step 1: Balance Equation
____H2SO4 + ____NaOH ____Na2SO4 + ____H2O
b. Step 2: Use this formula to solve for unknown concentration.
________________ = _________________
na = number of ____________ of your ____________ (Coefficient)
nb = number of ___________ of your _____________ (Coefficient)
M = _________________
V = __________________
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Neutralization Reactions can also be asked like this:
1. How many moles of HCl are needed to neutralize 6 mols of KOH?
a. 1st ask, what is the mol ratio and then set it up as a proportion.
2. H2SO4 + 2NaOH ↔ Na2SO4 + 2H2O
a. One mole of sulfuric acid is needed to neutralize moles of NaOH.
b. How many moles of NaOH are needed to neutralize 4 moles of H2SO4?
Neutralization and Titration Homework
1. What is the purpose of a titration?
2. Why do you need an indicator in a titration?
3. What is the endpoint?
4. Why is it important not to “overshoot” the titration? Refer to your answer to #1.
5. Calculate the molarity of an acetic acid solution if 34.57 mL of this solution are needed to neutralize 25.19 mL
of 0.1025 M of sodium hydroxide. Balance the equation as needed!!!!
____HC2H3O2 (aq) + ____ NaOH (aq) ____ Na C2H3O2 (aq) + _____ H2O (l)
6. 50 mL of 0.60 M sodium hydroxide neutralized 20 mL of sulfuric acid. Determine the concentration of the acid.
BALANCE THE EQUATION FIRST! ___ H2SO4 (aq) + ___ NaOH <-> ___ Na2SO4 (aq) + ___ H2O (l)
7. 25.0 mL of 0.10 M nitric acid neutralized 40.0 mL of barium hydroxide. Determine the concentration of the base.
BALANCE! ___ HNO3 (aq) + ___ Ba(OH)2 (aq) <-> ___ Ba(NO3)2 (aq) + ___ H2O (l)
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Acid/Base STUDY GUIDE
This is due on 4/26/16 and must be completed in its entirety to earn +5 points on the test.
Acid and Base definitions:
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1. What are the properties of acids? 2. What are the properties of bases?
3. Label as Acid (A), Base(B) or Salt(S) a. HCl _______
b. H3PO4 _______
c. HNO2 _______
d. LiOH _______
e. H2SO3 _______
f. H3P _______
g. Mg(OH)2 _______
h. NaCl _______
i. KNO3 _______
4. What are the products of the self-ionization reaction of water?
5. What does Kw stand for?
6. What is the value of Kw
7. Write the equation for Kw:
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8. Finish the equations:
pH =
pOH=
pH + pOH=
9. What is the range for the pH scale?
10. What is the equation used for a titration?
11. Write a complete and balanced equation for the following acid-base reaction:
a. H3PO4 + Ca(OH)2
b. HCl + Mg(OH)2
12. Calculate the concentration of hydrochloric acid if 125.0mL of this acid is neutralized by 60.0mL of 2.0M sodium
hydroxide? ____ HCl (aq) + _____NaOH (aq) ____ H2O (l) + ____ NaCl (aq)
13. Calculate the concentration of sulfuric acid if 60.0mL of this acid is neutralized by 10.0mL of .10M potassium hydroxide? ___ H2SO4 (aq) + ___ KOH (aq) <-> ___ K2SO4 (aq) + ___ H2O (l)
14. What is the molarity of 3.50 L of solution that contains 90.0g of sodium chloride?
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15. How many moles of HCl are present in 0.8 L of a 0.5M HCl solution?
16. How many milliliters of 16.0 M HNO3 would be required to prepare 750 mL of a 0.5 M solution?
17. Complete the chart:
remember Kw = [H+][OH-] and pH = -log[H+] and pH + pOH = 14
Given Solve for Acidic, Basic, or Neutral?
(A/B/N)
pH = 7 pOH =
pOH = 12.5 pH =
[H+] = 2.6 x 10 -4 pH =
[H+] = 1.0 x 10 -8 pH =
[OH-] = 1.0 x 10-10 [H+] =
[OH-] = 5.2 x 10-3 [H+] =
[H+] = 1.0 x 10 -7 [OH-] =
[H+] = 9.1 x 10 -13 [OH-] =
Kw = 1.00 x 10 -14 (mol/L)2