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Warm-up. What are some properties of acids and bases? According to the Brønsted-Lowry Model, what is the definition of an Acid? A Base? Describe the dissociation of a strong/weak acid. A strong/weak base. Describe the pH scale. What does it mean that the pH scale is logarithmic?

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Warm up
Warm-up

What are some properties of acids and bases?

According to the Brønsted-Lowry Model, what is the definition of an Acid? A Base?

Describe the dissociation of a strong/weak acid. A strong/weak base.

Describe the pH scale.

What does it mean that the pH scale is logarithmic?

What is the type of strong acid in our stomach?


Arrhenius model of acids and bases
Arrhenius Model of Acids and Bases

According to the Arrhenius Model:

Acidscontain _____________________ which then dissociate.

Basescontains ____________________ which then dissociate.

Acids and bases can _____________ electricity because the ______________.

Hydrogen (H+)

Hydroxide (OH-)


Br nsted lowry model of acids and bases 5b
BrØnsted-Lowry Modelof Acids and Bases 5b

Acids

substances thatare hydrogen-ion ____________.

Base

substancesthat are hydrogen-ion ____________

Donor

Acceptor


True or False.

All Bases with a Group 1 Metal (Alkali Metal) are Strong Bases…


If an Acid is strong its Conjugate Base is ________________________.

If a Base is a weak base than its Conjugate Acid is __________________.


Complete the following Acid Base Conjugate pairs. ________________________.

The Acid is always first. Complete the equation and label the Conjugate Base (CB) and Conjugate Acid (CA).

a)

HCO3–(aq) + S2–(aq)  HS–(aq) + CO32–(aq)

conjugate acid

conjugate base

acid

base

conjugate acid-base pairs

b)

H2CO3(aq) + OH–(aq)  HCO3–(aq) + H2O(l)

acid

base

conjugate base

conjugate acid

conjugate acid-base pairs


Complete the following Acid Base Conjugate pairs. ________________________.

Complete the equation and label the Conjugate Base (CB) and Conjugate Acid (CA).

c)

H3O+(aq) + HSO3–(aq)  H2O(l) + H2SO3(aq)

conjugate base

conjugate acid

acid

base

conjugate acid-base pairs

d)

HSO3–(aq) + OH–(aq) + )  H2O(l) + SO32–(aq)

conjugate acid

conjugate base

base

acid

conjugate acid-base pairs


Water as an acid and a base
Water as an Acid and a Base ________________________.

Water is _____________, because it can behave as either an acid or as a base



Strong acid – OH-completely ionized or completely dissociated

Weak acid –

most of the acid molecules remains intact


Acid strength
Acid Strength OH-

A strong acid contains a relatively weak conjugate base.

  • Common strong acids are

  • Sulfuric acid, H2SO4

  • Hydrochloric acid, HCl

  • Nitric acid, HNO3

  • Perchloric acid, HClO4

Oxyacid–

Strong Acids,

acidic proton is attached to an oxygen atom


Ph scale 5d
pH Scale 5d OH-

Describe the pH scale.

What does it mean that the pH scale is logarithmic?

  • pH is a measure of how much H+ a solution contains.

    • Lower pH contain more H + and less OH-

    • Higher pH contain less H + and more OH-

  • The scale is logarithmic, meaning an increase of 1 on the scale is actually a 10x increase!

    • A pH of 2 is actually 100x as acidic as a 4.


The ph scale
The pH Scale OH-

pOH scale

  • pOH = log [OH]

  • pH + pOH = 14.00


  • Measuring ph
    Measuring pH OH-

    Indicators – substances that exhibit different colors in acidic and basic solutions

    • In an acid solution the indicator will be in the HIn form.

    • In a basic solution the indicator will be in the In form.

    • Other methods

    • Indicator paper

    • pH meter


    You try 2
    You Try #2 OH-

    • Calculate pH for a solution that has

      [OH-] = 1.0 x 10-5 M.

      pH = 9.00


    You try 3
    You Try #3 OH-

    • Calculate pOH for a solution that has

      [H+] = 1.0 M

      pOH = 14.00


    You try 4
    You Try #4 OH-

    • Calculate pOH for a solution that has a

      pH = 6

      pOH = 8


    You try 5
    You Try #5 OH-

    • Calculate pH for a solution that has a

      pOH = 7

      pH = 7


    You try 6
    You Try #6 OH-

    • Calculate pH for a solution that has a

      pOH = 7.56

      pH = 6.44


    You try 7
    You Try #7 OH-

    • Calculate [OH-] for a solution that has a

      pH = 6.20

      pH = 1.6 x 10-8


    You try 8
    You Try #8 OH-

    • Calculate [OH-] for a solution that has a

      pH = 8.20

      pH = 1.6 x 10-6


    You try 9
    You Try #9 OH-

    • Calculate pH for a solution that has a

      [OH-] = 2.3 x 10-5

      pH = 9.36


    Buffers 5g
    Buffers 5g OH-

    • Buffers are substances that absorb or release H+ as needed to regulate the pH.

    • You have a buffer in your blood called bicarbonate

      • If the pH falls, it absorbs the extra H+

      • If the pH rises, it releases some H+

      • It keeps your blood neutral!

        H2CO3 H+ + HCO3-


    Neutralization reactions
    Neutralization Reactions OH-

    Both produce Salts when reacted with each other

    Neutralization reaction:

    An acid and a base react to form a salt and water.

    Salt: any ionic compound (metal & non-metal)

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

    ACID

    BASE

    SALT


    Salts
    Salts OH-

    Made up of a metal and a nonmetal.

    When dissolved in water, salts conduct electricity.


    Acid base titrations
    Acid-Base Titrations OH-

    Titration – delivering a measured volume of a solution of known concentration into the solution being analyzed

    Buret – device used for accurate measurement of the delivery of a liquid

    Equivalence Point) – the point at which neutralization occurs.


    Neutralization practice m a v a m b v b
    Neutralization Practice OH- MaVa = MbVb

    • Determine the volume of 0.100 M NaOH needed to titrate 50.0mL of 0.200 M HNO3

    • We need equals moles of H+ and OH-

    • HNO3 is a strong acid --> H+

    • NaOH is a strong base --> OH-

    • So…we get

      0.0500L x 0.200 M H+ = Vol x 0.100 M OH-

      Volume = 0.100L or 100 ml NaOH


    Neutralization practice 1 your turn m a v a m b v b
    Neutralization Practice #1 OH-(Your Turn) MaVa = MbVb

    • Determine the volume of 0.250 M KOH needed to titrate 25.0mL of 0.150 M HCl

    • We need equals moles of H+ and OH-

      Volume = 15.0 ml or 0.0150 L KOH


    Neutralization practice 2 your turn m a v a m b v b
    Neutralization Practice #2 OH-(Your Turn) MaVa = MbVb

    • Determine the volume of 0.200 M NaOH needed to titrate 75.0mL of 0.250 M HNO3

      Volume = 93.8 ml or 0.0938 L KOH


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