Unit 9: Acids, Bases, Salts Notes & CW · Unit 9: Acids, Bases, Salts Notes & CW. The. bold,...

Unit 9: Acids, Bases, Salts Notes & CWThe bold, underlined words are important vocabulary words that you should be able to define and use properly in explanations. This is a study guide for what you will be tested on throughout the year. The objectives are divided into categories of “Knowledge” (what you have to know) and “Application” (what you have to be able to do).

ACIDS, BASES, AND SALTS

Knowledge Application

1.

o The behavior of many acids and bases can beexplained by the Arrhenius Theory.

o Arrhenius acids produce H+ (hydrogen ions) asthe only positive ions in aqueous solution. Thehydrogen ion may also be written as H3O

+ andcalled the hydronium ion.

o Arrhenius bases produce OH– (hydroxide ions)as the only negative ion is aqueous solution.(Table E)

o Know the definitions of Arrhenius acids and bases

o If given the properties, chemical formula, or name,identify a substance as an Arrhenius acid orArrhenius base. (Use Tables K, L, and T to help youremember these definitions. Arrhenius acids begin with H,Arrhenius bases are metals + hydroxide ion(s). *Don’t befooled by alcohols, which also end in OH, but containcovalent bonds and do not ionize like bases do in solution.ALCOHOLS ARE NOT BASES!)

2.

o Arrhenius acids, Arrhenius bases, and salts (ioniccompounds) are all electrolytes. An electrolyte is asubstance which, when dissolved in water, forms asolution capable of conducting an electric current(electricity). Electrolytes can conduct electricitybecause they ionize (break apart into ions) in asolution.

o The ability of a solution to conduct an electriccurrent depends on the concentration of the ions init (more ions, more conduction).

o Given names or chemical formulas, identify acids,bases, and salts as being electrolytes

o Determine the relative strength (strong or weak)of an electrolyte given information on its abilityto ionize in solution.(Strong acids and strong bases are strong electrolytes –Tables K and L list acids and bases in order fromstrongest to weakest.If a salt is soluble, it is a strong electrolyte – Table F canbe used to determine the solubility of different salts.)

3.

o In the process of neutralization, an Arrhenius acidand an Arrhenius base react to form a salt andwater.

Acid + Base Salt + Water

o Recognize neutralization reactions when given thereaction equation

o Write neutralization reactions when given thereactants. (Remember that this is a double replacementreaction. Just switch the positive ions, look up theircharges and cross down the subscripts if needed. Thenbalance the equation.)

4.

o Titration is a laboratory process in which a volumeof solution with a known concentration is added toanother solution of unknown concentration.Titrations are done to determine the concentrationof the unknown solution.

o Calculate the concentration or volume of asolution, using titration data using the equation

Ma x Va = Mb x Vb (This equation is on Table T)

5. o There are alternate acid-base theories. One

such theory states that the acid is a proton donor(H+ donor) and the base is a proton acceptor.

o Give the alternate definitions of acids and baseso Use this definition to explain why ammonia is

considered a base

6.

o The acidity or alkalinity of an aqueous solutioncan be measured using the pH scale.

o The pH scale measures the concentration ofH+/H3O

+ in a solution. [H+] = 10–pH

A pH of 1 means that the [H+] = 10–1 = 0.1MA pH of 3 means that the [H+] = 10–3 = 0.001M

Acids have pH values between 0 and 7 (the stronger the acid, the lower the pH and the more H+)

[H+] [OH–]

Neutral solutions have a pH of 7 [H+] = [OH–]

Bases have pH values between 7 and 14 (the stronger the base, the higher the pH and the more OH–)

[H+] [OH–]

o Identify a solution as acidic, basic (alkaline), orneutral based upon the pH value OR the relativeconcentrations of H+/H3O

+ and OH–

o Describe acidic, basic, and neutral solutions interms of pH value and relative H+/H3O

+ and OH–

concentrationso Differentiate between strong acids/bases and

weak acids/bases given pH values or ionconcentrations

7.

o The pH scale is a logarithmic scale, which meansthat a change of one pH unit changes theconcentration of H+/H3O

+ by a factor of ten

tenfold = 10 times = 101

hundredfold = 100 times = 102

thousandfold = 1000 times = 103

The exponents represent the CHANGE in pHo If a solution becomes more acidic,

the pH , and the [H+]/[H3O+]

o If a solution becomes more basic,

the pH , and the [H+]/[H3O+]

o Determine the new pH value of a solution giventhe starting pH and the amount of increase ordecrease in [H+]/[H3O

+] (such as tenfold, ahundredfold, or a thousandfold)

Ex: A lake with an initial pH of 6 has been affected by acid rain. The acid rain has caused a hundredfold change in the [H+] concentration of the lake. What is the new pH of the lake?

Answer: pH = 4

o Determine the amount that the [H+]/[H3O+]

would increase or decrease given a certain changein pH

8.

o The pH of a solution can be shown by usingindicators.

o An indicator is a substance that changes colordepending on the concentration ofhydrogen/hydronium ions in a solution.

o Interpret changes in acid-base indicator coloro Explain how different indicators can be used to

distinguish between solutions with different pHvalues

o Identify appropriate indicators that can be used toshow changes in pH values, such as during atitration, given starting and ending pH values

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Lesson 1: Characteristic Properties of Acids:

__________ acids have a __________ tasteEx: citric acid (fruit), acetic acid (vinegar), carbonic acid (soda),

boric acid used as eye-washing solution

_______________ acids ______ skin & ___________ in clothing

Aqueous solutions of acids are __________________ (substancesthat conduct electric current when dissolved in water)

________ concentration of ____ = ______________________ ________ acids = ________ conductors ________ acids = ________ conductors

Acids react with ________ to form __________ solutions ________________________________ reaction Called a __________________ reaction _______ + _______ _______ + _______

Ex: __HCl(aq) + __NaOH(aq) → __ _______ + __ _______

Acids react with certain ________ to produce _______________ ________________________ reaction (Table J) _______ + _______ _______ + __________________

Ex: __HCl(aq) + __Na(s) → __ _______ + __ _______

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Acids cause acid-base _______________ to _________________ Ex: litmus paper turns red, phenolphthalein turns from pink to

colorless

Acids have ____________ < ___ (fall on _______ end of pH SCALE)

General formula = ___ or ___ (Where X = ________ such as ___ )

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ACIDIC NEUTRAL BASIC

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Characteristic Properties of Bases:

_________ bases have a _________ tasteEx: antacids, soaps, ammonia-based cleaning products

Bases have a _____________ or ___________ feel

_______________ bases ______ skin & ___________ in clothing

Aqueous solutions of bases are _________________ (substancesthat conduct electric current when dissolved in water)

__________ concentration of _____ = ___________________ ________ bases = _______ conductors ________ bases = _______ conductors

________ react with ________ to form __________ solutions ___________________________ reaction Called a __________________ reaction _______ + _______ _______ + _______

Ex: __HBr(aq) + __Ca(OH)2(aq) → __ _______ + __ _______

Bases cause acid-base _______________ to __________________ Ex: litmus paper turns blue, phenolphthalein turns from colorless

to pink

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Bases have ___________ > ___ (fall on _______ end of pH SCALE)

General formula = _____ (Where X = __________ such as ___ )

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Lesson 2: Characteristic Properties of Salts:

Defined as __________________________ that have ___________________________________ and _______________________________________; composed of a positively charged metal orpolyatomic ion AND a negatively charged nonmetal or polyatomic ion(with the exception of –OH- which would then make it a base)

Examples of salts ______, ______, ______, ______

Salts are FORMED FROM _______________________________and are _____________

Exception to the rule: NH4Cl is the salt of a weak acid

Electrolyte = A substance that _______________________ to form_______________ and therefore ___________________________

________, ________, & ________

ARE ALL ________________ (in _____________)

acid + base ______ + water

NH4Cl → _____ + Cl- NH4

+ is a weak acid, which means it produces H+ in solution

Classwork 9-1 & 9-2:

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Lesson 3: Acid/Base Theories An Arrhenius Acid is defined as a substance whose water (aqueous)solution contains or yields ____________ IONS (___ IONS) as the ___________________________ in solution

Examples: HCl H+

(aq) + Cl-(aq)

H2SO4 H+ + H+ + SO4-2

______ acids → ____________________________

GENERAL RULE FOR ACIDS: HYDROGEN (H) is the FIRST ION seen in the formula (H is always the POSITIVE ION)

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

** NOT ALL SUBSTANCES THAT CONTAIN HYDROGEN ARE ACIDS. Below is a list of covalent hydrogen compounds that do not dissociate to yield H+ ions.

Non-Examples of Acids: _______ = water (neutral & amphoteric) _______ = methane (natural gas) _______ = glucose (sugar) _______ = hydrogen peroxide _______ = ammonia (a weak BASE!!!)

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THE HYDRONIUM ION:

Let’s recall what happens when a hydrogen atom becomes an ion:

(Lose e-) H H+ + e-

Thus, a ______________________ is essentially a _________. When in water, this _________ is naturally ___________ to the unshared electrons and slight negative charge of the oxygen in the water. It is believed that the hydrogen ion cannot exist as an isolated particle so what forms is called a _____________________ (________).

According to the Arrhenius theory, the properties of acids are functions of these hydronium (hydrogen) ions. So, because of this, we say that H+ = H3O+

DIFFERENT TYPES OF ARRHENIUS ACIDS:

__________ acids (1 H+) acids that ionize in __________; acids that produce ______________ in solution

Ex: HCl ___ + ___


Ex: H2SO4 ___ + ________HSO4

- ___ + ________


Ex: H3PO4 ___ + ________ H2PO4

- ___ + ________ HPO4

2- ___ + ________

10

An Arrhenius Base is defined as a substance whose water (aqueous)solution contains or yields/produces ____ (_______________ IONS) as the ________________________________ when dissolved in water.

Examples: ___________, ____________

GENERAL RULE FOR BASES: contains –____ at the end of the formula

**One Exception to Rule: NH3 = ________________

_______________ Bases produce 1 –OH in aqueous soln (single step).

Example: KOH _____ + _____


Example: Ca(OH)2 _____ + _____


Example: Al(OH)3 _____ + _____

++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++

**Not all compounds that contain –OH are bases. For example, __________ and _________________ are _______________. Below is a list of compounds that contain –OH but do not dissociate to yield OH- ions.

Non-Examples of Bases: ______ = water (neutral & amphoteric) _______ = methanol (an alcohol) __________ = methanoic acid (an organic acid)

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Classwork 9-3:

1. Use Table K and Table L to help you identify the rules for determining whether a substance is anacid, a base, or a salt based on the formula. Underline all the acids, circle bases, and box in saltspurple. Leave the covalent substances alone.

NH3 NaCl CH3OH H2SO4 Ca(OH)2 CH4

NH4Br HCl Na2SO4 HNO3 CH3COOH NaOH

H3PO4 LiOH CH2(OH)2 NH4OH Ca(NO3)2 HC2H3O2

All acids have the _____________ ion in common.

All bases have the _____________ ion in common.

All salts have formulas that contain: _________________________________________________________________

Organic acids have the general formula: ________________

Draw ethanoic acid and show which H+ ion is lost:

Fill in the table indicating if the property is characteristic of an acid or base Property Acid or Base Property Acid or Base

Tastes sour Tastes Bitter Hydrolyzes Fats into

soap Reacts with active

metals to for H2 HCl(aq) KOH(aq) pH of 12 Forms H3O+

2. Which formula represents a hydronium ion?(1) H3O+ (2) OH– (3) NH4+ (4) HCO3–

3. Which compound is an Arrhenius acid?(1) H2SO4 (2) NaOH (3) KCl (4) NH3

4. Which substance is an Arrhenius acid?(1) Ba(OH)2 (2) H3PO4 (3) CH3COOCH3

(4)NaCl

5. Which compound releases hydroxide ions inan aqueous solution?(1) CH3COOH (2) HCl (3) CH3OH (4) KOH

6. The Arrhenius theory explains the behaviorof(1) acids and bases(2) alcohols and amines(3) isomers and isotopes(4) metals and nonmetals

7. Which two compounds are electrolytes?(1) C6H12O6 and CH3CH2OH(2) C6H12O6 and HCl(3) NaOH and HCl(4) NaOH and CH3CHOH

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10. An aqueous solution of lithium hydroxidecontains hydroxide ions as the only negative ionin solution. Lithium hydroxide is classified as an(1) aldehyde (3) Arrhenius acid(2) alcohol (4) Arrhenius base

11. Which compound is an Arrhenius acid?(1) H2SO4 (3) NaOH (2) KCl (4) NH3

12. An Arrhenius base yields which ion as the onlynegative ion in an aqueous solution?(1) hydride ion (3) hydronium ion(2) hydrogen ion (4) hydroxide ion

13. Which two formulas represent Arrhenius acids?(1) CH3COOH and CH3CH2OH(2) HC2H3O2 and H3PO4

(3) KHCO3 and KHSO4

(4) NaSCN and Na2S2O3

14. According to the Arrhenius theory, an acid is asubstance that(1) changes litmus from red to blue(2) changes phenolphthalein to pink(3) produces hydronium ions as the only positive ions in an aqueous solution (4) produces hydroxide ions as the only

negative ions in an aqueous solution

15. Which formula represents a hydronium ion?(1) H3O+ (2) OH– (3) NH4

+ (4) HCO3–

16. Which substance is an Arrhenius acid?(1) Ba(OH)2 (2) H3PO4 (3) CH3COOCH3 (4) NaCl

17. Which compound releases hydroxide ions in anaqueous solution?(1) CH3COOH (2) HCl (3) CH3OH (4) KOH

18. Which substance is an Arrhenius base?(1) CH3OH (2) LiOH (3) CH3Cl (4) LiCl

19. The only positive ion found in H2SO4(aq) is the(1) ammonium ion (3) hydronium ion(2) hydroxide ion (4) sulfate ion

20. Which substance, when dissolved in water,forms a solution that conducts an electriccurrent?(1) C2H5OH (3) C12H22O11

(2) C6H12O6 (4) CH3COOH

21. Which laboratory test result can be used to determine if KCl(s) is anelectrolyte?(1) pH of KCl(aq)(2) pH of KCl(s)(3) electrical conductivity of KCl(aq)(4) electrical conductivity of KCl(s)

22. Which substance is anelectrolyte?(1) CCl4 (3) HCl(2) C2H6 (4) H2O

23. Which substance, when dissolved in water, forms a solution that conducts an electriccurrent?(1) C2H5OH (3) C12H22O11(2) C6H12O6 (4) CH3COOH

24. Which substance is anelectrolyte?(1) CH3OH (3) H2O(2) C6H12O6 (4) KOH25. A solid substance was tested in the laboratory. The test results are listed below.

• dissolves in water• is an electrolyte• melts at a high temperatureBased on these results, the solid substance could be(1) Cu (3) C(2) CuBr2 (4) C6H12O6

26. Which formula represents anelectrolyte?(1) CH3OCH3 (3) CH3COOH(2) CH3OH (4) C2H5CHO27. The compound HNO3 can be described asan (1) Arrhenius acid and an electrolyte(2) Arrhenius acid and a nonelectrolyte(3) Arrhenius base and an electrolyte(4) Arrhenius base and a nonelectrolyte

28. Which compound is an electrolyte?(1) C6H12O6 (3) CaCl2(2) CH3OH (4) CCl4

29. Which 0.1 M solution contains an electrolyte?

(1) C6H12O6 (aq) (3) CH3 OH(aq)(2) CH3 COOH(aq) (4) CH3 OCH3 (aq)

30. Based on Reference Table F, which of these salts is the bestelectrolyte?A. sodium nitrateB. magnesium carbonateC. silver chlorideD. barium sulfate

31. A substance that conducts an electrical current when dissolved in water iscalled (1) a catalyst (3) a nonelectrolyte(2) a metalloid (4) an electrolyte

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32. Which compound is an Arrheniusacid?(1) CaO (3) K2O(2) HCl (4) NH3

33. Which compound when dissolved in water is an Arrheniusacid?(1) CH3OH (3) NaCl(2) HCl (4) NaOH

34. When one compound dissolves in water, the only positive ion produced in thesolution is H3O+(aq). This compound is classified as(1) a salt(2) a hydrocarbon(3) an Arrhenius acid(4) an Arrhenius base

35. The Arrhenius theory explains thebehavior of (1) acids and bases(2) alcohols and amines(3) isomers and isotopes(4) metals and nonmetals

36. Which substance is an Arrheniusacid?(1) Ba(OH)2 (3) H3PO4(2) CH3COOCH3 (4) NaCl

37. Which compound releases hydroxide ions in an aqueoussolution?(1) CH3COOH (3) HCl(2) CH3OH (4) KOH

38. Which compound is an Arrhenius acid?(1) H2SO4 (3) NaOH(2) KCl (4) NH3

39. An Arrhenius base yields which ion as the only negative ionin an aqueous solution?(1) hydride ion (3) hydronium ion(2) hydrogen ion (4) hydroxide ion40. Which ion is the only negative ion produced by anArrhenius base in water?(1) NO3– (3) OH–(2) Cl– (4) H–

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41. The Arrhenius theory explains thebehavior of (1) acids and bases(2) alcohols and amines(3) isomers and isotopes(4) metals and nonmetals

42. Which ion is the only negative ion present in an aqueous solution of an Arrheniusbase?(1) hydride ion (3) hydronium ion(2) hydrogen ion (4) hydroxide ion

43. When an Arrhenius acid dissolves in water, the onlypositive ion in the solution is(1) H+ (3) Na+(2) Li+ (4) K+

44. Which substance is an Arrheniusbase?(1) KCl (3) KOH(2) CH3Cl (4) CH3OH

45. The compound HNO3 can be describedas an (1) Arrhenius acid and an electrolyte(2) Arrhenius acid and a nonelectrolyte(3) Arrhenius base and an electrolyte(4) Arrhenius base and a nonelectrolyte

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Lesson 4: Alternate Acid-Base Theory (AKA ________________ Theory)

This theory explains the behavior of _____________ & ______________

Definitions of the Theory:

BRONSTED-LOWRY _______ are the _______________________ ___________________________________________________

Circle the B-L Acid below:

BRONSTED-LOWRY _______ are the _______________________ ___________________________________________________

Circle the B-L Base below:

Bronsted-Lowry Conjugate Pairs:

We will use TWO BRACKETS connecting one side of the reaction to the other to represent the ACID-BASE CONJUGATE PAIRS (each member within the pair DIFFERS from the other BY MERELY ONE HYDROGEN)

HCl(aq) + H2O(l) H3O+(aq) + Cl-(aq)

Notice: The acid always has one more H than the base!

KEY A = Acid B = Base CA = Conjugate Acid CB = Conjugate Base

H2O + + OH -

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Use brackets and the key from the example on the previous page to indicate the conjugate pairs in the equations below.

Practice Problem 1:

NH3 + HOH NH4+ + OH-

Practice Problem 2:

HCl + HOH Cl- + H3O+

Practice Problem 3:

HI + HOH I- + H3O+

Practice Problem 4:

HNO3 + H2O H3O+ + NO3-

1. One acid-‐base theory defines a base as an(1) H+ donor (2) H donor (3) H+ acceptor (4) H acceptor

2. One alternate acid-‐base theory states that an acid is a(n)(1) H+ donor (2) OH− donor (3) H+ acceptor (4) OH− acceptor

3. According to one acid-‐base theory, a water molecule acts as an acid when the water molecule(1) accepts an H+ (2) accepts an OH– (3) donates an H+ (4) donates an OH–

4. Given the equation representing a reaction at equilibrium:NH3(g) + H2O(l) ßà NH4+(aq) + OH–(aq)

The H+ acceptor for the forward reaction is (1) H2O (l) (2) NH4+ (aq) (3) NH3 (g) (4) OH– (aq)

5. Which formula represents a hydronium ion?(1) H3O+ (2) OH– (3) NH4+ (4) HCO3–

6. Given the balanced equation representing a reaction:NH3(g) + H2O (l) ßà NH4+(aq) + OH–(aq)

According to one acid-‐base theory, the NH3(g) molecules act as (1) an acid because they accept H+ ions (2) an acid because they donate H+ ions (3) a base because they accept H+ ions (4) a base because they donate H+ ions

7. Which statement describes an alternate theory of acids and bases?(1) Acids and bases are both H+ acceptors.(2) Acids and bases are both H+ donors.(3) Acids are H+ acceptors, and bases are H+ donors.(4) Acids are H+ donors, and bases are H+ acceptors.

8. Which substance, when dissolved in water, forms a solution that conducts an electric current?(1) C2H5OH (2) C12H22O11 (3) C6H12O6 (4) CH3COOH

Classwork 9-4:

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Lesson 5: The pH Scale - The Power of Hydrogen:

pH = direct measurement of _______________________ in a solution

The pH scale is designed to measure ___________ or ____________ an aqueous solution is. The concentration of hydronium and hydroxide ions in a solution will determine whether a solution is acidic or basic.

The pH scale ranges from ___ TO ___ (ACIDIC neutral BASIC)

In an acidic substance [H+] > [OH-] (brackets indicate concentration) In a basic substance [H+] < [OH-] In a neutral substance [H+] = [OH-] Example: H2O

The pH of a solution is the negative log of the [H+]:

pH = -log[H+]

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If the [H+] is in the form 1 X 10-x then the pH = x Examples:

Solution A has [H+] = 1 X 10-2 then the pH = __________________ Solution B has [H+] = 1 X 10-8 then the pH = __________________Solution C has [H+] = 1 X 10-6 then the pH = __________________

Solution D has [H+] = 1 X 10-13 then the pH = __________________

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For basic solutions, find the pOH using the negative log of the [OH-], then subtract that value from 14 to get the pH:

pOH = -log[OH-]

pH = 14 – pOH

Each change of a SINGLE pH UNIT signifies A TENFOLD CHANGE IN [H+] CONCENTRATION

Ex: A change from a ph of 4 to a pH of 5

Becomes more/less basic; [OH-] increases/decreases by a factor of

____

Becoming more/less acidic; [H+] increases/decreases by _______

Ex: A change from a pH of 13 to a pH of 10

Becoming more/less acidic; [H+] increases/decreases by _______

Becoming more/less basic; [OH-] increases/decreases by _______

If the [OH-] is in the form 1 X 10-x then the pOH = x

Solution A has [OH-] = 1 X 10-2 then the pOH = ____ and pH = _____ Solution B has [OH-] = 1 X 10-8 then the pOH = _____ and pH = _____Solution C has [OH-] = 1 X 10-6 then the pOH = _____ and pH = _____

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(Where some common substances fall on the pH scale)

STRONG acids and bases ionize 100%:

Strong base (sodium hydroxide): NaOH (s) _____ + _____ (100% ionization)

Strong acid (hydrochloric acid): HCl(g) _____ + _____(100% ionization)

WEAK acids and bases have < 100% ionization (partial ionization)

Weak acid (acetic acid): HC2H3O2 ______ + _________(partial ionization)

Weak Base (ammonia): NH3 + H2O ______ + ______

(partial ionization)

Strong Acids Strong Bases

HCl LiOH

HBr NaOH

HI KOH

H2SO4 RbOH

HNO3 CsOH

HClO4 Ba(OH)2

Sr(OH)2

Ca(OH)2

*Ammonia and the –OH in water battle for hydrogen. Roughly 1/10,000 times, ammonia wins, generating a SLIGHT excess of OH – ions, making the solution BASIC.

tdolgos

Placed Image

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The pH scale is a measure of the H+ or H3O+ concentration in a solution. “pH” stands for “potential to ATTRACT Hydrogen ions” “potential to ATTRACT Hydrogen ions

Ø Acids have a LOW pH (a LOW potential to attract H+ ions (release/DONATE H+) Ø Bases have a HIGH pH (a HIGH potential to attract H+ ions (bases are H+ acceptors)

The pH scale is logarithmic, which means that a change of one pH unit will change the concentration of H+ by a factor of 10.

1. Label the pH scale below in terms of acid, base and neutral.

1 2 3 4 5 6 7 8 9 10 11 12 13 14

2. Complete the table using the grid below:

Hydronium Ion Concentration (M) pH Acid or Base? Stomach fluids

Lemon Juice

Blood

Seawater

Bleach

Classwork 9-5:

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3. Circle one to complete the tableIf an ACID is added… If a BASE is added…

pH Increases or Decreases Increases or Decreases

[H+] or [H3O+] Increases or Decreases Increases or Decreases

[OH–] Increases or Decreases Increases or Decreases

Solution becomes

more Acidic or Basic Acidic or Basic

Recall the following: § increasing or decreasing the pH by 1 changes the [H+] by a factor of 101 (10 times, “ten-‐

fold”) § increasing or decreasing the pH by 2 changes the [H+] by a factor of 102 (100 times,

hundred-‐fold) § increasing or decreasing the pH by 3 changes the [H+] by a factor of 1000 (thousand-‐

fold)

4. Describe what happens to the concentration of hydrogen ions in a solution if the pH is changedfrom 7 to 5.

5. Describe what is happening to the concentration of hydrogen ions in a solution if the pH ischanged from 5 to 8.

6. Complete the table below:

pH Change

[H3O+] increase or decrease?

[OH-‐] increase or decrease?

Does the solution become more acidic or

basic?

By a factor of…

6 to 8 8 to 5 3 to 7 11 to 9 14 to 13 4 to 8

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4. Which of these pH numbers indicates the highestlevel of acidity?

(1) 5 (2) 10 (3) 8 (4) 12

5. Which change in pH represents a hundredfoldincrease in the concentration of hydronium ions in a solution?

(1) pH 1 to pH 2 (3) pH 2 to pH 1 (2) pH 1 to pH 3 (4) pH 3 to pH 1

6. The pH of a solution changes from 4 to 3 whenthe hydrogen ion concentration in the solution is

(1) decreased by a factor of 100 (2) decreased by a factor of 10 (3) increased by a factor of 100 (4) increased by a factor of 10

7. Solution A has a pH of three and solution Z has apH of six How many times greater is the hydronium ion concentration in solution A than the hydronium ion concentration in solution Z?

(1) 100 (2) 3 (3) 2 (4) 1000

8. What is the pH of a solution that has ahydronium ion concentration 100 times greater than a solution with a pH of 4?

(1) 5 (2) 3 (3) 2 (4) 6

9. As the pH of a solution is changed from 3 to 6, the concentration of hydronium ions(1) increases by a factor of 3(2) increases by a factor of 1000(3) decreases by a factor of 3(4) decreases by a factor of 1000

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Lesson 6: Acid-Base Indicators (Table M):

Indicator = substance (weak acid) that _________________ as a result of a ________________; indicators are chosen based on their __________ for ___________________

Ex: Phenolphthalein COLORLESS up until a pH of 8, LIGHT PINK from 8 to 9, and PINK at a pH greater than 9

Ex: Methyl Orange turns RED in a solution with a pH of less than 3.1, ORANGE between 3.1 and 4.4, and YELLOW in a solution with a pH greater than 4.4

*Litmus listed is liquid litmus (similar to paper litmus)** Within the “Approximate pH Range for Color Change” a MIXTURE

OR BLENDING of the two colors listed occurs. This range is therefore also called the INTERMEDIATE COLOR REGION.

1. bromthymol blue at a pH of 6.4 ____________________2. bromcresol green at a pH of 5.0 ____________________3. phenolphthalein at a pH of 9.2 ____________________4. methyl orange at a pH of 3.9 ____________________

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Using reference table M, complete the chart below.

Indicator pH of sample Color indicator will turn

methyl orange 6.0

bromothymol blue 2.0

phenolphthalein 7.0

Litmus 6.8

bromocresol green 3.0

thymol blue 7.0

methyl orange 2.2

bromothymol blue 8.2

phenolphthalein 10

Litmus 3.2

bromocresol green 6.2

thymol blue 10

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Table M

Ex: If you add bromthymol blue… to a solution with a pH of 8, it will be blue to a solution with a pH of 6, it will be green to a solution with a pH of 4, it will be yellow

1. Which indicator, when added to a solution,changes color from yellow to blue as the pH of the solution is changed from 5.5 to 8.0?

(1) bromcresol green (2) bromthymol blue (3) litmus (4) methyl orange

2. Which indicator would best distinguish betweena solution with a pH of 3.5 and another with a pH of 5.5?

(1) bromthymol blue (3) litmus

(2) bromcresol green (4) thymol blue

3. In which solution will bromcresol green appearblue?

(1) 1 M NaCl (3) 1 M NH3 (2) 1 M H2CO3 (4) 1 M CH3COOH

4. In which solution will thymol blue indicatorappear blue?

(1) 0.1 M CH3COOH (3) 0.1 M KOH (2) 0.1 M HCl (4) 0.1 M H2SO4

5. What is the color of the indicator methyl orangein a solution that has a pH of 2?

(1) blue (3) yellow (2) orange (4) red

6. In a solution with a pH of 3, what color isbromcresol green?

(1) yellow (3) green (2) blue (4) red

7. At what pH will bromothymol blue be yellowand bromocrescol gree be blue?

(1) 10.5 (2) 5.7 (3) 7.0

8. A student used blue litmus paper and phenolphthalein paper as indicators to test the pH of distilledwater and five aqueous household solutions. Then the student used a pH meter to measure the pH of the distilled water and each solution. The results of the student’s work are recorded in the table below.

a) Identify the liquid tested that has the lowest hydronium ion concentration.

b) Explain, in terms of the pH range for color change on Reference Table M, why litmus is notappropriate to differentiate the acidity levels of tomato juice and vinegar.

c) Based on the measured pH values, identify the liquid tested that is 10 times more acidic thanvinegar.

How to use Table M: Ø If the pH is below the first number, the solution will be the first color listed Ø If the pH is above the second number, the solution will be the second color listed Ø If the pH is between the numbers, the solution will be a mix of the two colors

Classwork 9-6:

28

pH & Indicators:

Given the pH of the following common substances determine what color the indicator will turn when placed in each substance.

Substance pH Methyl Orange

Bromthymol Blue

Phenolphthalein Litmus Bromcresol green

Thymol blue

Stomach Acid

2

Cola Drink 3

Blood 7.5

Pure Water

7.0

Oven Cleaner

14

Tomatoes 4

Milk 6.5

Detergent 10

Coffee 5

Household Cleaners

11

29

pH:pH is a scale that measures the hydronium ion (H+) concentration of a solution. A pH of less than 7 indicates an acidic solution. A solution with a pH of 7 is neutral. A solution with a pH of 7 to 14 is basic and contains a higher concentration of hydroxide ions than hydronium ions. Indicators are substances that change color in the presence of certain ions. Phenolphthalein is colorless in an acid and a neutral solution, but pink in a base. Litmus is red in an acid and blue in a base. This is outlined on Table M of the Reference Tables. For each of the following substances indicate the pH range expected: acid = pH < 7, neutral = pH = 7, or base = pH > 7. Also indicate the color the indicator will appear based on these values. Finally, state if the substance is an acid (A) or a base (B).

Solution PH range Methyl Orange

Thymol Blue

Litmus Brom- Cresol Green

Phenol- Phthalein

Bromo Thymol

blue

Acid or Base?

Vinegar 1.3

Soap 8.4

Cola 3.2

Ammonia 12

Rain 6.4

Milk of Magnesia

8.1

Milk 6.6

Saliva 6.5

Coffee 5.2

Gastric juices 1.5

Human blood 7.4

OJ 2.1

Kool-Aid 6.4

Drain cleaner 1.8

Bleach 6.2

Shampoo 6.3

31

Sam

Oval

32

Lesson 7: Neutralization Reactions:

Neutral = neither acidic nor basic; [H+] = [OH-]

Neutralization occurs when an Arrhenius acid and an Arrhenius base react to form __________ and a ___________

Example: Antacid for upset stomach neutralizes the acid in stomach and makes a neutral salt to provide relief

General reaction for neutralization reactions:

(1) The ___ from the acid and the ___ from the base combine to form water.

(2) The ________ from the acid and the ________ from the base combine to produce a salt.

*Neutralization rxns are always _____________________ reactions!**Remember, just like any compound, the (+) and (-) charges must be

balanced. Use the Criss Cross Rule to figure out the correct formula for the salt – water is always the formula H2O!

Net ionic equation for neutralization reactions (after spectator ions are crossed out):

H+(aq) + OH-(aq) H2O(l)

ACID + BASE _______ + _______

33

Complete the following reactions. Make sure they are balanced!

1. HBr + KOH __________ + __________

2. NaOH + HC2H3O2 __________ + __________

3. KOH + H3PO4 __________ + __________

4. 2HNO3 + Ca(OH)2 __________ + __________

34

Neutralization

Neutralization Reactions: If equal mole amounts of acid and base are added together, the resulting solution is NEUTRAL! )

Acid + Base → Salt + Water

Example: HCl (aq) + NaOH (aq) → NaCl (aq) + H2O (l)

1. Predict the products of and balance the following reactions:

___ HF (aq) + ___ LiOH (aq) → __________ (aq) + ___ HOH (l)

___ HNO3 (aq) + ___ KOH (aq) → __________(aq) + ___ HOH (l)

___ HCl (aq) + ___ Ca(OH)2 (aq) → __________(aq) + ___ HOH (l)

___ HClO3 (aq) + ___ Mg(OH)2 (aq) → __________(aq) + ___ HOH (l)

___ H2CO3 (aq) + ___ NaOH (aq) → __________(aq) + ___ HOH (l)

2. What are the products of a reaction betweenKOH(aq) and HCl(aq)? (1) H2 and KClO (3) H2O and KCl (2) KH and HClO (4) KOH and HCl

3. Which word equation represents aneutralization reaction? (1) base + acid →salt + water (2) base + salt →water + acid (3) salt + acid →base + water (4) salt + water →acid + base

4. Which compound could serve as a reactant in aneutralization reaction? (1) NaCl (3) CH3OH (2) KOH (4) CH3CHO

5. Which substance is always a product when anArrhenius acid in an aqueous solution reacts with an Arrhenius base in an aqueous solution? (1) HBr (3) KBr (2) H2O (4) KOH

6. Which reactants form the salt CaSO4(s) in aneutralization reaction? (1) H2S(g) and Ca(ClO4)2(s) (2) H2SO3(aq) and Ca(NO3)2(aq) (3) H2SO4(aq) and Ca(OH)2(aq) (4) SO2(g) and CaO(s)

Classwork 9-7:

35

7. Sulfuric acid, H2SO4(aq), can be used toneutralize barium hydroxide, Ba(OH)2(aq). What is the formula for the salt produced by this neutralization? (1) BaS (3) BaSO3 (2) BaSO2 (4) BaSO4

8. Which chemical equation represents thereaction of an Arrhenius acid and an Arrhenius base? (1) HC2H3O2(aq) + NaOH(aq) à NaC2H3O2(aq) + H2O(l) (2) C3H8(g) + 5 O2(g) à 3 CO2(g) + 4 H2O(l) (3) Zn(s) + 2 HCl(aq) à ZnCl2(aq) + H2(g) (4) BaCl2(aq) + Na2SO4(aq) à BaSO4(s) + 2 NaCl(aq)

When an acid dissolved it dissociates or ionizes (breaking up into two ions). The ions are separated due to the polarity of water, as shown below in the 1st box. Draw what happens to the acid, base, and salt in water in the other boxes.

HCl(g) + H2O(l) à HCl(aq) HNO3(g) + H2O(l) à HNO3(aq) NaOH(g) + H2O(l) à NaOH(aq) NaCl(g) + H2O(l) à NaCl(aq)

+ +

-‐

Cl-‐

H+

36

Lesson 8: (Acid-Base) Titration:

Titrations are used to CALCULATE THE CONCENTRATION (MOLARITY) OF AN UNKNOWN SOLUTION

Acid of unkown molarity is reacted with a carefully measuredamount of a base of known molarity to the point of_____________________ (or vice versa)

In all neutralization reactions there must be a _____________ between the ______________________ and the ______________________

So, in a titration, when: _______ = _______

or ______________________ = ______________________

that means you’ve reached the _____________________ of the reaction; this is when the titration is complete. The ______________ of a titration is the pH at which the solution changes color permanently.

What does a Titration look like?

Titration formula (Table T): MA VA = MB VB

Where: MA = molarity of acid (H+) VA = volume of acid MB = molarity of base (OH-) VB = volume of base

Use this formula when you are dealing with atitration or neutralization word problem

Make sure that all units are in agreementwhen plugging into formula (so they cancel outand you get the right answer!)

37

Sample Problem 1: What is the concentration of a solution of HI if 0.3 L is neutralized by 0.6 L of 0.2 M solution of KOH?

Sample Problem 2: What is the concentration of a hydrochloric acid solution if 50.0 mL of a 0.250 M KOH solution are needed to neutralize 20.0 mL of the HCl solution of unknown concentration?

Sample Problem 3: A particular acid has an H+ concentration of 0.1 M and a volume of 100 mL. What volume of a base with a 0.5 M [OH-] will be required to neutralize the reaction?

**Sample Problem 4: You have 50 mL of 1.0 M H2SO4(aq). What volume of 0.5 M NaOH would be required to neutralize the acid? Remember Diprotic Acids yield 2 H+ ions in solution!

Lab - Hydronium vs. Hydroxide: A Battle to the End Point

It is sometimes necessary to experimentally determine

the concentration of an acid solution or a base solution. A

procedure used for this is called an acid-base titration. In

this procedure, a solution of known concentration, called the

standard solution, is used to neutralize a precisely measured

volume of the solution of unknown concentration, to which an

indicator has been added. If the solution of unknown

concentration is acidic, a standard base solution is added to

the acid solution until neutralized. If the solution of unknown

concentration is basic, a standard acid solution is added to the

base solution until it is neutralized.

When carrying out an acid base titration, you must be

able to recognize when to stop adding the standard solution

(when the point of neutralization is reached). This is the

purpose of the indicator. A sudden change in color of the indicator signals that neutralization has

occurred. At this point, the number of hydrogen ions H+ (or hydronium ions, H3O+) from the acid equals

the number of hydroxide ions (OH-) from the base. The point at which this occurs is called the endpoint

of the titration. The volumes of the standard solution and the unknown solution are measured, and

applied to the following equation:

MaVa= MbVb

Ma =Molarity of the acid solution Mb = Molarity of the basic solution

Va =Volume of the acid solution Vb = Volume of the basic solution

Objective: In this experiment you will determine the molarity of an unknown HCl with a standard

solution of 1.0 M NaOH .

The equation for this reaction is: NaOH(aq) + HCl(aq) NaCl(aq) + H2O(l)

Materials and Equipment:

burette stand, burette clamp, 100 ml graduated cylinder, 25 mL graduated cylinder, 250 mL

Erlenmeyer flask, 2 - 250 mL beakers, dropper bottle of phenolphthalein, distilled water and funnel

Procedure:

1. Put on goggles. Keep them on until your instructor gives the OK for everyone to remove them.

2. Label two beakers: A (for acid) and B (for base).

(Standard Solution -Known Concentration)_

(Solution of unknown

concentration)

38

3. In Beaker A obtain approximately 75 mL of acid, and in Beaker B obtain 75 mL base from the stock

bottles. Record the known concentration of the base on your Data sheet.

4. Rinse the burette with distilled water. Let it run out into the sink. Then rinse once with 5-10 mL of

base. Again let it run into the sink with the faucet slowly running. Then close the stopcock. It

should be perpendicular to the burette.

5. Hold the top of the burette at eye level or slightly below. Using the funnel, carefully add the base to

the burette. Go about an inch past the top line on the burette, being careful not to let it overflow.

Then again hold the burette over the sink. Open the stopcock and let excess base run into the sink

(while you run water) until the base in the burette is at or just below the 0 mark. This allows any

trapped air bubbles to be removed. Now place the burette in its holder.

6. Record the initial volume of the base in the burette to the nearest 0.1 mL in the table.

7. Rinse out the graduated cylinder and Erlenmeyer flask with distilled water. Use the graduated

cylinder and a pipette to measure out about 20 mL of the acid. Record the exact amount in the

data table to the nearest 0.1 mL. Carefully pour into the Erlenmeyer flask.

8. Use the dropper pipet to add 2 to 3 drops of phenolphthalein to the flask.

9. Put the flask under the burette. Put a piece of white paper underneath it. The tip of the burette

should be within the flask.

10. Slowly add base to the flask, while constantly swirling the flask. The pink color should fade with

swirling. When the pink color persists for longer periods, add the base more slowly until you are

adding it drop by drop.

** It is titrated when 1 drop of base causes a pink color that persists for 10-20 seconds (with swirling)

and then disappears. At this point, your solution is at the end point.

11. Record the final volume of the base in the burette in the table to the nearest 0.1 mL.

12. Dump the contents of the flask down the drain。Repeat the experiment from Step 6 above. If the

burette need to be refilled, make sure you record the new initial volume.

13. When done with both trials, drain the burette down the drain while running water. Rinse burette

with distilled water. Hang burette upside down on the burette clamp with paper towel underneath.

Rinse out the burette funnel with water. Dispose of excess acid and base from the beakers as

directed. Clean up and return supplies.

14. Do calculations and answer questions.

39

Data: Concentration of standard solution of base: Mb = 1.0 M

Trial 1: (Ma)HCl volume = 20.0 mL Trial 2: (Ma)HCl volume = 20.0 mL

NaOH NaOH

initial volume

(mL)

initial volume

(mL)

final volume

(mL)

final volume

(mL)

(Vb) volume

used(mL) (Vb)volume used

(mL)

Calculations: For each trial, calculate the molarity of the HCl(Ma) solution. Show all work (equation

used, substitution of values, and answer with correct units.)

Trial 1:

Trial 2:

MaVa= MbVb MaVa= MbVb

40

41

1. What are the products of a reaction betweenKOH(aq) and HCl(aq)?

(1) H2 and KClO (2) H2O and KCl (3) KH and HClO (4) KOH and HCl

2. Which word equation represents a neutralizationreaction?

(1) base + acid →salt + water (2) base + salt →water + acid (3) salt + acid →base + water (4) salt + water →acid + base

3. Which compound could serve as a reactant in aneutralization reaction? (1) NaCl (3) CH3OH (2) KOH (4) CH3CHO

4. Which substance is always a product when anArrhenius acid in an aqueous solution reacts with an Arrhenius base in an aqueous solution? (1) HBr (3) KBr (2) H2O (4) KOH

5. Which reactants form the salt CaSO4(s) in aneutralization reaction? (1) H2S(g) and Ca(ClO4)2(s) (2) H2SO3(aq) and Ca(NO3)2(aq) (3) H2SO4(aq) and Ca(OH)2(aq) (4) SO2(g) and CaO(s)

6. Sulfuric acid, H2SO4(aq), can be used toneutralize barium hydroxide, Ba(OH)2(aq). What is the formula for the salt produced by this neutralization? (1) BaS (3) BaSO3 (2) BaSO2 (4) BaSO4

7. Which chemical equation represents thereaction of an Arrhenius acid and an Arrhenius base? (1) HC2H3O2 + NaOHà NaC2H3O2 + H2O (2) C3H8+ 5 O2 à3 CO2 + 4 H2O (3) Zn + 2 HClà ZnCl2 + H2 (4) BaCl2 + Na2SO4 à BaSO4 + 2 NaCl

8. Which volume of 0.10 M NaOH(aq) exactlyneutralizes 15.0 milliliters of 0.20 M HNO3(aq)? (1) 1.5 mL (3) 3.0 mL (2) 7.5 mL (4) 30. mL

9. In which laboratory process could a student use0.10 M NaOH(aq) to determine the concentration of an aqueous solution of HBr? (1) chromatography (2) decomposition of the solute (3) evaporation of the solvent (4) titration

10. The data collected from a laboratory titrationare used to calculate the (1) rate of a chemical reaction (2) heat of a chemical reaction (3) concentration of a solution (4) boiling point of a solution

11. Which volume of 0.10 M NaOH(aq) exactlyneutralizes 15.0 milliliters of 0.20 M HNO3(aq)? (1) 1.5 mL (3) 3.0 mL (2) 7.5 mL (4) 30. mL

12. What volume of 0.120 M HNO3(aq) is needed tocompletely neutralize 150.0 milliliters of 0.100 M NaOH(aq)? (1) 62.5 mL (3) 180. mL (2) 125 mL (4) 360. mL

Classwork 9-8:

42

Titrations are procedures used to determine the concentration (M) of an acid or a base. You combine

together an acid and a base knowing the volume of each and the concentration of only one of them.

Titration Problems

1. A 25.0-‐milliliter sample of HNO3 (aq) is neutralized by 32.1 milliliters of 0.150 M KOH (aq). What isthe concentration of the acid?

2. How many milliliters of 0.200 M NaOH are needed to neutralize 100. mL of 0.100 M HCl?

Titration setup

Erlenmeyer flask containing ACID AND an indicator

buret containing BASE

buret containing BASE

1. What number would be at thetop of the buret?

2. Read the volume of the base inthe buret.

3. If the buret holds 50mL, howmuch base is actually in theburet?

4. If a student started at 2.0mLand released base until it wasat the level shown, how muchbases was added?

5. Why is it not necessary tosubtract all your volumes from

43

3. In a titration, 20.0 milliliters of 0.15 M HCl(aq) is exactly neutralized by 18.0 milliliters of KOH(aq).

(a) Complete the equation below for the neutralization reaction by writing the formula of each product.

KOH(aq) + HCl(aq) → _________ + _________

(b) Compare the number of moles of H+(aq) ions to the number of moles of OH– (aq) ions in the titration mixture when the HCl(aq) is exactly neutralized by the KOH(aq).

(c) Determine the concentration of the KOH(aq).

(d) What is the new pH of the solution?

1. In a laboratory activity, 0.500 mole of NaOH(s) is completely dissolved in distilled water to form400. milliliters of NaOH(aq). This solution is then used to titrate a solution of HNO3(aq).

(a) Identify the negative ion produced when the NaOH(s) is dissolved in distilled water.

(b) Calculate the molarity of the NaOH(aq). Your response must include both a correct numerical setup and the calculated result.

(c) If 26.4 milliliters of the NaOH solution is needed to exactly neutralize 44.0 milliliters of the HNO3 solution, what is the molarity of the HNO3 solution?

(d) Complete the equation below representing this titration reaction by writing the formulas of the products.

44

Exceptions:

H3PO4 + H2O à 3H3O+ + PO4-‐3 H2SO4 + H2O à 2H3O+ + SO4-‐2 What happens when an acid has two or more hydrogen atoms? Do they just lose one? Strong acids completely ionize leaving no hydrogen atoms in the anion or conjugate base. This means we need to amend out titration formula for these special acids to include all the acidic ions that come off.

Ca(OH)2 + H2O à 2OH-‐ + Ca+2 Mg(OH)2 + H2O à 2OH-‐ + Mg+2Similarly, what happens when a base has two or more hydroxide ions? Do they just lose one? Strong bases completely ionize leaving no hydroxide ions in the cation. This means we need to amend our titration formula for these special bases to include all the basic ions that come off.

The MaVa = MbVb formula will have coefficients in front of the M corresponding to the number of H+ or OH-‐ in the acid and base formula.

Example: If 35.0mL of 3.00M H3PO4 is neutralized by 50.0mL of Ca(OH)2, what is the molarity of the base?

MaVa = MbVb becomes 3 Ma Va = 2 Mb Vb 3(3)(35) = 2(x)(50) x = 3.15M

1. If 65.0mL of 1.50M H3PO4 is neutralized by 25.0mL of Ca(OH)2, what is the molarity of the base?

2. If 15.0mL of 3.50M H2SO4 is neutralized by 25.0mL of Mg(OH)2, what is the molarity of the base?

3. If 150.0mL of 4.50M HNO3 is neutralized by 3.00M Mg(OH)2, what is the volume of the base added?

45

4. If 25.5mL H3PO4 is neutralized by 50.0mL of 2.00M LiOH, what is the molarity of the acid?

5. If 35.0mL of H2CO3 is neutralized by 50.0mL of 1.50M KOH, what is the molarity of the acid?

6. If 6.00M HI is neutralized by 50.0mL of 4.50M RbOH, what is the volume of the acid added?

More Practice:

1. A 25.0-‐milliliter sample of HNO3(aq) is neutralized by 32.1 milliliters of 0.150 M KOH(aq). What is themolarity of the HNO3(aq)?

2. A 25.0 mL sample of 5.00 M HCl is required to neutralize 34.5 mL of NaOH solution, what is theconcentration of the NaOH solution?

3. A total of 50.0 mL of 0.50 M KOH solution completely neutralizes 125 mL of hydrobromic acid solution(HBr). Calculate the concentration of the HBr solution.

4. What volume of 0.10 M NaOH(aq) exactly neutralizes 15.0 milliliters of 0.20 M HNO3(aq)?

46

Lesson 9: Reactions of Metals with Acids:

According to Table J in your Reference Tables, any __________ LOCATED ______________________________________ to produce _____________________

Example: Which metal, Mg or Cu will react with HCl? ________

General Rxn:

Ex: Zn + 2HCl ____ + _____

Of the four types of reactions that we have learned, this is a ____________ _______________ reaction; notice how __________ is produced!

Ex: ___, ___, & ___ do not react with acids because they are located ___________ on Table J (notice these are metals used for JEWELRY!)

Classwork 9-9:

47

27

Unit Review: Acids, Bases, Salts

Place a checkmark next to each item that you can do! If a sample problem is given, complete it as evidence.

_____1. I can still do

everything from Unit 1.















_____10. I can use two

different systems to define

acids and bases.

Arrhenius “Alternate Method” (AKA

Bronsted-Lowry)

acid

base

_____11. I can define pH, [ ],

hydronium ion, hydroxide ion,

and electrolyte.

Definitions: pH

[ ]

hydronium ion

hydroxide ion

electrolyte

28

_____9. I can state another

name for the hydronium ion.

The hydronium ion is also known as the ____________________

__________.

_____10. Given the hydronium

ion concentration, I can

determine the pH.

If the [H3O+] is 1 x 10-8, the pH of the solution will be________.




_____11. Based on pH, I can

determine if a solution is

acidic, basic, or neutral.

If the pH of a solution is 4.5, the solution is ____________________.


If the pH of a solution is 11, the solution is ____________________.


_____12. I can state the

relationship between H+

concentration and pH.

As the H+ concentration decreases , the pH _______________________.

As the H+ concentration increases, the pH

_________________________.

_____13. I can determine the

change in pH when the H+

concentration of a solution is

changed.

If the H+ concentration is increased by a factor of 10,

the pH will decrease by ____________.

If the H+ concentration is increased by a factor of 100,

the pH will decrease by ______________.

If the H+ concentration is decreased by a factor of 1000,

the pH will increase by _______________.

_____14. I can give examples of

the chemical names of common

acids and bases.

List the chemical names of three common acids and three common bases.

Acids Bases

29

_____15. I can give examples of

chemical formulas of common

acids and bases.

List the chemical formulas of three common acids and three common

bases.

Acids Bases

_____16. I can define

neutralization.

Definition:

neutralization

_____17. I can identify a

neutralization reaction from a

list of reactions.

Which of the following equations is a neutralization reaction?

A) 6Na + B2O3 -----> 3Na2O + 2 B

B) Mg(OH)2 + 2HBr -----> MgBr2 + 2HOH

C) 2H2 + O2 -----> 2H2O

D) 2KClO3 -----> 2KCl + 3O2

_____18. I can state the name

of the laboratory equipment

that is used to carry out a

titration.

Which piece of laboratory equipment is used to carry out a titration?

_____19. I can state the

purpose of titration.

Why do scientists do titrations?

_____20. I can solve for any

variable in the titration

equation from Reference Table

T.

If it requires 56.95 mL of 0.0043 M HNO3 to neutralize 34.56 mL of

LiOH, what is the concentration of the LiOH?

_____21. I can state the three

types of substances that are

electrolytes.

_______________, _________________, and _________________ are

three classes of compounds that are electrolytes.

_____22. Given the pH, I can

determine the color of acid-

base indicators.

Which indicator is red in a solution that has a pH of 3.6?

A) bromcresol green

B) bromthymol blue

C)litmus

D) thymol blue

71

Part 1: Acid Rain Webquest

Visit the following website to thoroughly answer the next five questions using your own words. http://www.epa.gov/acidrain/education/site_students/whatisacid.html

First watch the “Acid Rain Simulation” to get an overview. Then answer the following

questions based on what you learned. You may also navigate through the website to help answer each of the questions.

1. What is acid rain?

2. What are causes of some acid rain?

3. Why is acid rain harmful?

4. What is being done to reduce acid rain?

5. What can you do to help reduce acid rain?

Visit the following website to thoroughly answer the next five questions using your

own words. http://www.softschools.com/facts/weather/acid_rain_facts/575/

6. When was acid rain first recognized?

7. When did people begin to note the crisis and looked for solutions?

8. What is the general pH range of acid rain?

9. What emissions do power plants produce that contribute to acid rain?

http://www.epa.gov/acidrain/education/site_students/whatisacid.html

http://www.softschools.com/facts/weather/acid_rain_facts/575/

72

10. What emissions do vehicles produce that contribute to acid rain?

11. What consumer products have similar pH values as acid rain?

Visit the following website to thoroughly answer the next five questions using your

own words. https://ypte.org.uk/factsheets/acidrain/theeffectsofacidrain#section

12. How does acid rain spread?

13. Why is nitrogen a problem?

14. How can the damage be restored?

15. What can be done to help reduce acid rain?

16. Describe how mass transit would play a role in diminishing acid rain.

https://ypte.org.uk/factsheets/acid-rain/the-effects-of-acid-rain#section

73

Part 2: Acid Rain Simulation

Background

Acid rain and vinegar have similar pH values. Over the next week you will observe and record the effect that vinegar has on an egg shell.

Materials 25 ml vinegar

One uncooked egg Glass container with lid

pH paper with pH chart Graduated cylinder Small paint brush

Safety

Always wear safety goggles when handling chemicals in the lab. Wash your hands thoroughly before leaving the lab. Follow the teacher’s instructions for cleanup of materials and disposal of

chemicals. When working with acids, if any solution gets on your skin immediately rinse

the area with water.

Procedure

1. Carefully place a single egg inside one of the glass containers.2. Record your qualitative observations about the egg shell in the data table

(color, hardness, etc.)3. Measure 25 ml of vinegar in a graduated cylinder.4. Pour all the vinegar onto the egg in the jar. Using the paint brush, apply the

vinegar to the shell of the egg, so that the entire surface has been saturatedwith vinegar.

5. Touch the paint brush to a strip of pH paper. Compare the color change withthe pH color chart. Record the pH value in the data table.

6. Seal the jar with the lid, and place the jar in a safe place.

7. After 24 hours return to the jar.8. Remove the lid, and dip your paint brush in the jar and touch it to a new

piece of pH paper. Record this value in your data table.9. Again record your qualitative observations about the egg shell in the data

table, specify color, hardness, etc. Wear gloves if you remove the egg from

the jar.10. Seal the jar with a lid, and place the jar in a safe place.

11. Repeat steps 7-9 several times during a week (complete 3-4 observationsafter the first day).

12. After a week, wearing gloves remove the egg from the jar and gently rinse

the egg with water. Record your final observations.

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Observations

Observation pH value Qualitative Observations

Initial (Day 1)

Second (Day __)

Third (Day __)

Fourth (Day __)

Final (Day 7)

Analysis

1. How does the pH of vinegar compare with the average pH of acid rain? Referto your webquest if needed.

2. What indicators of chemical change did you observe on the egg shell duringthe week trial?

3. Research to find out what the main chemical component of an egg shell is.Record its chemical name and chemical formula.

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4. Research to find out what the acid in vinegar is called. Record its chemicalname and chemical formula.

5. What kind of reaction took place between the egg shell and the vinegar?

Conclusion

What other materials contain the same chemical as the one found in egg shells?

Reflect on the egg and vinegar reaction, why was this done, and how was it helpful

as you learned about acid rain?

Unit 9: Acids, Bases, Salts Notes & CW · Unit 9: Acids, Bases, Salts Notes & CW. The. bold,...

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Transcript of Unit 9: Acids, Bases, Salts Notes & CW · Unit 9: Acids, Bases, Salts Notes & CW. The. bold,...