Drill pd 4A
5/20/2015
What do you do if you spill acid in
the lab?
Do you add acid to water or water to
acid?
Drill pd 3
5/19/15
What do you do if you spill acid in
the lab?
• Tell your instructor immediately
• Place baking soda (base) over it to neutralize
and clean up with paper towels.
Do you add acid to water or water to
acid?
• Acid to water
Objectives
SWBAT:
• Define acid rain and it’s effects on our
environment
• list major differences between acids and
bases
• list products of neutralization reactions
• distinguish between 2 methods of defining
acids and bases.
• list properties of a salt
Agenda
• Notes on Acids and Bases (50 mins)
• Worksheets
Acid Rain
• Look at the following pictures on
the powerpoint. From the pictures
and your own experiences, what
are some of the damaging effects
of acid rain?
Acids and Bases
Properties of Acids (in aq solution)
1.
2.
3.
4.
Sour taste
Low pH
Turn blue litmus paper red
Conduct electrical current
Properties of Bases (in aq solution)
1.
2.
3.
4.
5.
Bitter taste
Slippery
High pH
Turn red litmus paper blue
Conduct electrical current
What happens when Mg
reacts with HCl??
• Hydrogen gas is produced
(popping noise we heard in earlier
lab)
Indicators
• Substance that turns 1 color in
acidic solutions and another in
basic solutions.
• Examples: phenolphthalein (used
in bio) and litmus paper (made
from a species of lichen)
Acid-Base Reactions
• Known as a neutralization
reaction. Acids and bases will
react with each other to form salt
and water.
A + B  Salt + H2O
HCl + NaOH  NaCl + H2O
Characteristics of Salts
•
•
•
•
Electrolytes
Ionic compounds
High melting points
Products of neutralization
Arrhenius Definition
Acid = substance that releases H+ ions
in aq solution
HCl  H+ + Cl-
Base = substance that releases OHions in aq solution
NaOH  Na+ + OHNeutralize each other: H+ + OH-  H2O
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 Definition
• Acid = proton donor
H2O + HCl  H3O+ + Cl-
Bronsted-Lowry Definition
• Base = proton acceptor
NH3 + H2O  NH4+ + OH–
Drill - pd 3
5/20/15
Identify the following as acid or base.
HBr + H20  H30+ + BrWrite balanced neutralization equations for the
following reactants:
1. HBr and NaOH
2. H2SO4 and NH4OH
3. H2CO3 and NaOH
Answers to Drill
• The reaction of an acid and a base results in the
formation of a salt and water. The process is
known as neutralization.
• HBr + NaOH ------> NaBr + H2O
• H2SO4 + 2 NH4OH -----> (NH4)2SO4 + 2H2O
• H2CO3 + 2 NaOH --> Na2CO3 + 2 H2O
•
Announcement
• Pass forward Lab Notebooks
please.
Agenda
• Go over Acid Base WS
• Homework:
– Conjugate Acids and Bases WS
– Naming Acids WS
• When water gains a proton it is
called HYDRONIUM.
+
H3O
• When water loses a proton it is
called HYDROXIDE.
OH
Acids & Bases Review
• Acid
– substance that releases H+ ions in aq solution
– Proton donor
• Base
– substance that releases OH- ions in aq
solution
– Proton acceptor
H2O is both an acid and a base
Water is simultaneously donating and
accepting protons = amphoteric
substance
Conjugate Acids & Bases
• Conjugate acid – what is produced
when a base gains a H+ ion
• Conjugate base – what is produced
when an acid loses a H+ ion
• Conjugate base pair – two
substances related to each other by
the donating and accepting of a single
H+ ion
Conjugate acid-base pairs
HF + H2O
acid
base
H3O + F –
conjugate conjugate
acid
base
Conjugate Pairs Inverse
Relationship
• The stronger the acid, the weaker its
conjugate base
• The stronger the base, the weaker its
conjugate acid
HCO3 + H2O  H3O + CO3
weak A
strong B
weak
C.A.
strong
C.B.
Naming Acids
1. Binary – contains hydrogen & one
other element
– Start with hydro– Then element
– End with –ic acid
Ex. HCl = hydrochloric acid
HBr = hydrobromic acid
Naming Acids
2. Oxyacids – Contains both hydrogen
& oxyanion = polyatomic ion containing
one or more oxygen atoms (NO2, SO4)
• If anion ends in –ate then the acid ends
in –ic
“I ate something, and now I am sick”
• If the anion ends in –ite then the acid ends
in –ous
Ex. HNO2 = nitrous acid, HNO3 = nitric acid
Your Turn
• Name the following acids and bases:
1.HClO3
2.H2SO3
3.NaOH
4.NH4OH
5.HI
Your Turn
• Name the following acids and bases:
1.HClO3 – chloric acid
2.H2SO3 – sulfurous acid
3.NaOH – sodium hydroxide
4.NH3OH – ammonium hydroxide
5.HI – hydroiodic
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
Nitric acid
Hydrochloric
Sulfuric acid
Sulfurous acid
Acetic acid
Hydrobromic acid
Nitrous acid
Phosphoric acid
Hydrosulfuric
Carbonic acid
Homework
• Conjugate Acid-Base Pairs WS
Acid Strength
A stronger acid will react completely to
form ions (strong electrolytes) and
hydronium ions (H3O+) in water.
Hydrochloric acid (all HCL molecules are
ionized into hydronium and chloride ions)
HCl + H2O  H3O+ + ClAcetic Acid (not all A.A. molecules are ionized
into hydronium and ions)
CH3COOH + H2O  H3O+ + CH3COO-
Examples of Strong & Weak Acids
Strong
HCl
HBr
H2SO4
Weak
CH3COOH
H2CO3
HClO
Objectives
• SWBAT compare the strength of a
weak acid with the strength of its
conjugate base
• SWBAT explain the relationship
between acid and base strength and
the values of their ionization
constants.
Base Strength
• A strong base has the strongest
affinity for H+ ions and dissociates
entirely into metal ions and OH-.
• For ex. Calcium oxide (CaO); oxygen
strongly attracts H+ ions.
• Strong bases: CaO, NaOH, KOH
• Weak base: ammonia (NH3)
Conjugate Pairs Inverse
Relationship
• The stronger the acid, the weaker its
conjugate base
• The stronger the base, the weaker its
conjugate acid
HCO3 + H2O  H3O + CO3
weak A
strong B
weak
C.A.
strong
C.B.
Sample Problem
• Write an equation to show the
dissociation of hydrochloric acid
in water.
Answer
HCl + H2O → H3O+ + Cl−
• HCl is a STRONG ACID
Sample Problem
• Write an equation to show the
dissociation of the hydrogen
carbonate ion in water.
Answer
HCO3 + H2O  H3O+ + CO3-
• The hydrogen carbonate ion
(HCO3-) is a WEAK ACID
How can the strength of an acid or
base be quantified?
Measure the amount of hydronium ions
created (acids) or the amount of
hydroxide ions created (bases)
by calculating dissociation constants.
Acid Dissociation Constant
HA + H2O  H3O+ + AHA = acid (H = hydrogen, A = rest of
acid molecule
A = rest of acid after H+ is removed
[ ] = concentration
Ka = [H3O +] [A-]
[HA]
Acid Dissociation Constant
• For HClO2, show the dissociation Rx
and write the expression for it in
terms of Ka
• HClO2 + H2O  ClO2 - + H3O+
Ka = [H3O +] [A-]
[HA]
Ka = [H3O +] [ClO2 -]
[HClO2]
Your Turn
• For HNO2 show the dissociation Rx
and write the expression for it in
terms of Ka
• HNO2 + H2O  NO2 - + H3O+
Ka = [H3O +] [A-]
[HA]
Ka = [H3O +] [NO2 -]
[HNO2]
Acid Dissociation Constant
• The larger the dissociation value, the
more the acid reacts with water to
produce hydronium ions, therefore
the stronger the acid
• Weak acids have values less than 1
(only small fraction of acid molecule
dissociates in water)
Base Dissociation Constant
B + H2O  HB+ + OHB = base
HB = B after H+ is added
[ ] = concentration
Kb = [HB+] [OH-]
[B]
Base Dissociation Constant
• For C6H13NH2, show the dissociation
Rx and write the expression for it in
terms of Ka
C6H13NH2 + H2O  C6H13NH3+ + OH Kb = [HB+] [OH-] Kb = [C6H13NH3+][OH-]
[B]
[C6H13NH2]
Your Turn
• For HSO3-, show the dissociation Rx
and write the expression for it in terms
of Ka
HSO3- + H2O  + H2SO3 + OH Kb = [HB+] [OH-] Kb = [H2SO3 ] [OH-]
[B]
[HSO3- ]
Base Dissociation Constant
• The stronger the base, the larger the
concentration of OH- ions and the
larger the Kb.
• Weak bases have a Kb less than 1.
Acid & Bases Lab: Litmus Test
1.
Predict if substance is acidic, basic or neutral
and record in 2nd column of WS.
2.
Show me your predictions before going to lab.
3.
Test the 18 substances using red and blue
litmus paper. Record your results in columns 3 &
4 of table by placing a  under a category if
acidic or basic. If no reaction, no . Place used
litmus papers on paper towel on top of runway.
4.
Show me your work before conducting pH test.
Acid & Bases Lab: pH Test
1. For each substance, record the color that the
pH paper changed to after you dipped it into
the solution.
2. Record the pH value that matches with the
color on the pH paper.
Assignment
• 18-2 Review and Reinforcement –
due tomorrow.
• Cross out #9.
• Cross out Practice Probs on the back
– not required to do these types of
problems!
What is concentration?
• Using molarity, it is a measure of
moles of solute in liters of
solution.
• Concentration is measured in
WATER!
Question
• Who is taking an AP test next
week and when?
Homework DUE
• Titration Lab
Announcements
• Review – two worksheets
• Test – May 16 (4B) or May 19 (4A)
Agenda
•
•
•
•
•
Review Titration Problems
Finish up Acids and Bases
Titration Problems
Review Sheet 1
Review Sheet 2
Homework
• Titration Practice – front side only
• Review Worksheets
Test Topics
•
•
•
•
•
•
•
•
Properties of acids, bases, and salts
Bronsted-Lowry definition of acids/bases
Lewis definition of acids/bases
Amphoteric substance
Neutralization reaction – must be balanced
Naming acids
Calculating pH, pOH, [H+], and [OH-]
Titration calculations
Lewis Definition of Acids/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
Announcement
• Make up Titration Lab and Help
available afterschool today.
Agenda/Announcements
• Acids and Bases Quest postponed
until tomorrow.
• Make-up date = Monday, May 21.
• Go over Acids and Bases Review
Sheet
• Hand in Titration Lab Calculations
Drill #65
5/17/12
• Write the balanced neutralization
equations for the following reactions:
1. carbonic acid & calcium hydroxide
2. potassium hydroxide and acetic acid
3. barium hydroxide and hydrochloric
acid
What are the ion concentrations in water?
• The concentrations of H3O+ and
OH- in pure water are each
1.0×10-7 mol/L at 25ºC.
• Putting a symbol in brackets is
used to signify the concentration.
• [H30+] = 1.0×10-7 M
• [OH-] = 1.0×10-7 M
Ionization Constant of water, KW
• KW = [H30+] [OH-]
• KW = (1.0×10-7)(1.0×10-7)
= 1.0×10-14
• Acids increase the
Whenever [H30+] is
greater than [OH-], the
solution is acidic.
• Bases increase the [OH-]
Whenever [OH-] is
greater than [H30+], the
solution is basic.
[H30+]
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
• Concentration values tend to be
small…so we use a more
convenient scale. pH!
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 [H3
+
0]
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 ]
• The logarithm scale is created to
make numbers over a large range
more manageable.
• 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 = ?
• 10? = x
Log 100 = ?
10 ? = 100
• Remember, our concentrations
are SMALL. So we are going to
be dealing with decimals…
• Log 10 x = ?
• 10? = x
Log .001 = ?
10 ? = .001
[H+] = 1×10-3 = 0.001
pH = -log [H+]
pH = -log (1×10-3)
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.
• For a base, you do the same
thing except remember that you
are solving for pOH first…
Ionization Constant of water, KW
• KW = [H30+] [OH-]
• KW = (1.0×10-7)(1.0×10-7)
= 1.0×10-14
Solutions
1.0×10-3M
HClO4
0.010 M HCl
0.000001 M
KOH
6.00×10-4
HBr
0.20 M NaOH
0.00300 H2SO4
[H+]
pH
[OH-]
1.0×10-3M
3.0
1.0×10-11M
11
1.0×10-2M
2.0
1.0×10-12M
12
8
1×10-6M
6
6.00×10-4M
3.22
1.67×10-11M
10.8
5.0×10-14M
13
2.0×10-1M
.70
6.00×10-3M
2.22
1.67×10-12M
11.8
1×10-8M
pOH
Drill – 5/12/11
• Calculate the hydronium ion
concentration in a 0.000500 M
solution of NaOH.
• What is the pH?
Green Workbook
•
•
•
•
•
Pg. 262 #2
Pg. 264 #1
Pg. 267 #3
Pg. 269 #1 & #2
Pg. 270 #7
Equations to Know!!
• [H30+] [OH-] = 1.0×10-14 M
• pH + pOH = 14
• pH = -log [H30+]
• pOH = -log [OH ]
• [H30+] = 10-pH
• [OH-] = 10-pOH
Drill – 5/9/11
• Write the equation for the
neutralization reaction between
carbonic acid (H2CO3) and
calcium hydroxide.
Agenda
• Gallery Walk – record notes from
posters on Guided Notes sheet.
Stay out of lab area
• Topics include:
– Props of acids and bases
– Arrhenius definition of an acid and a base
– Bronsted-Lowry definition of an acid and base
– Determining the strength of acids and bases
– Acid dissociation constant
– Naming and Identifying acids and bases
Drill 54 – 5/2/2012
• What do you think are properties
of acids? Of bases?
Drill #57
5/7/2012
• Do you add acid to water or water
to acid?
• AAA
• Always Add Acid to water
• AW
Drill #63
5/15/12
• A solution of KOH is titrated with
HCL. The pH is measured as the HCl
is added to the flask. The value of the
pH will
• Please be patient with me today, I
barely have a voice!
Drill #63
5/15/12
• A solution of KOH is titrated with
HCL. The pH is measured as the HCl
is added to the flask. The value of the
pH will decrease.
Homework Due
• Naming Acids WS
Assignment
• Bronsted-Lowry Acids & Bases WS
• Titration Curve Data Graph
Drill #9
5/5, 5/6/2014
Homework Due
• Bronsted-Lowry Acids & Bases WS
• Keep Titration Graph