Acids and bases
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Acids and Bases. Drill – 5/6/11. What happens when you mix an acid and a base?. Drill – 5/9/11. Write the equation for the neutralization reaction between carbonic acid (H 2 CO 3 ) and calcium hydroxide. Drill – 5/11/11.

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Acids and Bases

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Acids and bases

Acids and Bases


Drill 5 6 11

Drill – 5/6/11

  • What happens when you mix an acid and a base?


Drill 5 9 11

Drill – 5/9/11

  • Write the equation for the neutralization reaction between carbonic acid (H2CO3) and calcium hydroxide.


Drill 5 11 11

Drill – 5/11/11

Identify the following as acid, base, conjugate acid, and conjugate base:

HBr + H20  H30+ + Br-


Acids and bases

ACIDS & BASES


Properties of acids in aq solution

Properties of Acids (in aq solution)

  • Sour taste

  • Low pH

  • Turn litmus paper red

  • Conduct electrical current


Properties of bases in aq solution

Properties of Bases (in aq solution)

  • Bitter taste

  • Slippery

  • High pH

  • Turn litmus paper blue

  • Conduct electrical current


Arrhenius definition

Arrhenius Definition

Acid = substance that releases H+ ions in aq solution

HCl  H+ + Cl-

Base = substance that releases OH-ions in aq solution

NaOH  Na+ + OH-


Acid base reactions

Acid-Base Reactions

  • Known as a neutralization reaction. Acids and bases will react with each other to form salt and water.

    HCl + NaOH  NaCl + H2O


Bronsted lowry definition

Bronsted-Lowry Definition

As more and more substances were determined to have acidic or basic properties, even some without obvious H+ or OH-, a new definition was needed.

  • Acid = proton donor

  • Base = proton acceptor


Bronsted lowry definition1

Bronsted-Lowry Definition

  • Acid = proton donor

    H2O + HCl  H3O+ + Cl-


Bronsted lowry definition2

Bronsted-Lowry Definition

  • Base = proton acceptor

    NH3 + H2O  NH4+ + OH–


Acids and bases

  • Lewis Acid – something that accepts an electron pair to form a covalent bond

  • Lewis Base – something that donates an electron pair to form a covalent bond

    A + :B → A—B


Acids bases review

Acids & Bases Review

  • Acid

    • substance that releases H+ ions in aq solution

    • Proton donor

    • Electron pair acceptor

  • Base

    • substance that releases OH-ions in aq solution

    • Proton acceptor

    • Electron pair donator


Acid naming overview

Acid Naming Overview

Binary

Start with hydro-

Element

End with –ic acid

Tertiary (Oxyacids)

“I ate something, and now I am sick”

If anion ends in –ate then the acid ends in –ic

If the anion ends in –ite then the acid ends in -ous


Acid strength

Acid Strength

A stronger acid will transfer MORE protons (H+) than a weak acid. It will create more hydronium ions (H3O+) in water.

Hydrochloric acid

HCl + H2O  H3O+ + Cl-

Acetic Acid

CH3COOH + H2O H3O+ + CH3COO-

More dissociation!

Less dissociation!


Acids and bases

How do we compare the strength of an acid or a base?

We measure the amount of hydronium ions they create (acids) or the amount of hydroxide ions they create (bases)….using concentration.


Acids and bases

  • When water gains a proton it is called HYDRONIUM!!

    H3O+


Acids and bases

  • When water loses a proton it is called HYDROXIDE!!

    OH-


What is concentration

What is concentration?

  • Using molarity, it is a measure of moles of solute in liters of solution.

  • Concentration is measured in WATER!


Acids and bases

*New Info*


H 2 o is both an acid and a base

H2O is both an acid and a base

Water is simultaneously donating and accepting protons!


What are the ion concentrations in water

What are the ion concentrations in water?

  • The concentrations of H3O+ and OH- in pure water are each 1.0x10-7 mol/L at 25ºC.

  • Putting a symbol in brackets is used to signify the concentration.

  • [H30+] = 1.0x10-7 M

  • [OH-] = 1.0x10-7 M


Ionization constant of water k w

Ionization Constant of water, KW

  • KW = [H30+] [OH-]

  • KW = (1.0x10-7)(1.0x10-7) = 1.0x10-14


Acids and bases

With an increase in [H30+], some of the H30+ ions will react with the OH- ions, reducing [OH-] . [H30+][OH-] will still = 1.0x10-14

  • Acids increase the [H30+] Whenever [H30+] is greater than [OH-], the solution is acidic.

  • Bases increase the [OH-]

    Whenever [OH-] is greater than [H30+], the solution is basic.


Acids and bases

  • Concentration values tend to be small…so we use a more convenient scale. pH!


Ph poh 14

pH + pOH = 14

  • pH – A measure of the acidity of a solution. It is the negative logarithm of the hydronium ion [H30+] concentration.

    pH = -log [H30+]


Ph poh 141

pH + pOH = 14

  • pOH – A measure of how basic a solution is. It is the negative logarithm of the hydroxide [OH-] concentration.

    pOH = -log [OH-]


Acids and bases

  • The logarithm scale is created to make numbers over a large range more manageable.


Acids and bases

  • The logarithm base 10 of a number x is the power to which 10 must be raised in order to equal x.

  • Log 10 x = ?Log 100 = ?

  • 10? = x10 ? = 100


Acids and bases

  • Remember, our concentrations are SMALL. So we are going to be dealing with decimals…

  • Log 10 x = ?Log .001 = ?

  • 10? = x10 ? = .001


Acids and bases

[H+] = 1 x 10-3 = 0.001

pH = -log [H+]

pH = -log (1 x 10-3)

pH = 3

To determine pH from a concentration where 1 is the only digit, write the concentration in scientific notation. The absolute power of the exponent will be the pH.


Acids and bases

  • For a base, you do the same thing except remember that you are solving for pOH first…


Ionization constant of water k w1

Ionization Constant of water, KW

  • KW = [H30+] [OH-]

  • KW = (1.0x10-7)(1.0x10-7) = 1.0x10-14


Acids and bases

3

11

1.0x10-3M

1.0x10-11M

2

12

1.0x10-2M

1.0x10-12M

8

6

1x10-8M

1x10-6M

10.8

3.22

6.00x10-4M

1.67x10-11M

13

.70

2.0x10-1M

5.0x10-14M

2.22

11.8

6.00x10-3M

1.67x10-12M


Drill 5 12 11

Drill – 5/12/11

  • Calculate the hydronium ion concentration in a 0.000500 M solution of NaOH.

  • What is the pH?


Equations to know

Equations to Know!!

  • [H30+] [OH-] = 1.0x10-14

  • pH + pOH = 14

  • pH = -log [H30+]

  • pOH = -log [OH-]

  • [H30+] = 10-pH

  • [OH-] = 10-pOH


Acids and bases

  • Let’s look at pg. 260 in the green workbook.


Green workbook

Green Workbook

  • Pg. 262 #2

  • Pg. 264 #1

  • Pg. 267 #3

  • Pg. 269 #1 & #2

  • Pg. 270 #7


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