Bellwork
12-7-2015
In the reaction of potassium carbonate with
hydrochloric acid, carbon dioxide gas is formed
along with water and a salt. If 62.5 g of K2CO3
is used with 147.8 mL of 1.0 M HCl, determine
the theoretical yield of the salt.
Learning Targets
1.
2.
3.
I CAN write and balance the equation for an acidbase neutralization reaction.
I CAN describe the differences between dissociation
and ionization. *review
I CAN draw and describe the neutralization of an
acid by a base (reactants and products).
What makes something an acid?
Usually sour tasting
Corrosive
Burn skin
Can be helpful
Releases H+
Example of Acid
Stomach Acid
Orange Juice
Lemonade
Vinegar
Acids in Reactions
Acids ‘donate’ a proton or H+ to a reaction
HCl + NaOH  NaCl + H(OH)


Monoprotic- an acid that can donate only 1 proton to
a base (HCl)
Diprotic- an acid that has two ionizable hydrogen
atoms in each molecule, such as sulfuric acid (H2SO4)
What makes something a base?
Taste bitter and feel slippery
Settle Upset Stomachs
Burn Skin
Detergents and many cleaning solutions
A base releases hydroxide ions (OH-) in water
Examples of Bases
Bleach
Egg White
Detergent
Bases in Reactions
Bases ‘donate’ a hydroxide ion or OH- to a reaction
HCl + NaOH  NaCl + H(OH)
When acids and bases meet

Neutralization Reaction
3KOH + H3PO4  K3PO4 + 3HOH
base
acid
salt
water
Drawing neutralization reactions

Define & describe:
Dissolve
Dissociate
Ionize
Precipitate
Ionic Compounds
Cation (metal) attracted to an anion (non-metal)
 Positive and negative ions interact with the polar
water molecules
 Dissolve AND dissociate in water

https://www.youtube.com/watch?v=CLHP4r0E7hg
Molecular Compounds



Two non-metals covalently bonded
Some dissolve in water, some ionize, meaning the
molecule splits up into two charged ions.
This happens in many acid-base reactions… for
example, hydrochloric acid (HCl) ionizes in water and
splits up into a dissolved hydrogen ion and a dissolved
chloride ion.
In the following problems, write out the balanced
reaction and identify the acid, base and salt
Barium Hydroxide is mixed with Sulfuric Acid
(H2SO4)
Water and potassium nitrate are the products of
an acid-base reaction.
Try #1-4 on Page 3
Acid and Base Scale
Acids pH from 0 to 7
Neutral pH is 7
Base pH from 7 to 14
pH is a measure of hydrogen ion concentration
pH = -log[H+]
pH means what?

Concentration of H+ ions

pH = -log[H+]

Therefore, the more H+ the lower the concentration
H+
H+
H
H+
H+
H+
H+
H+
H+
H+
H+
H
H+
H+
H+
H+
H+
H+
H+
H+
Example Calculation

Calculate the pH of hydrochloric acid with a H+
concentration of 5.69 x 10-1
pH = -log[H+]
pH = -log[5.69 x 10-1]
pH = 0.245
Practice Calculation
What is the pH of a 1.2 x 10-3 HBr solution?
2.9
What is the pH of a 2.34 x 10-5 HNO3 solution?
4.63
Try #5-9 on Page 4
Bellwork 12-8-2015
Liquid A has a pH of 10,
Liquid B has a pH of 3
Liquid C has a pH of 7
1. Which liquid could be pure water?
2. Rank the liquids in order from most acidic
to least acidic.
3. Which liquid might be a solution of
sodium hydroxide?
4. Which liquid has the fewest hydroxide
ions dissolved in water?
5. Which liquid might be hydrochloric acid?
Checking In!
pH Base:
7-14
pH Neutral:
7
pH Acid:
0-7
Answers:
1.C
2.B>C>A
3.A
4.B
5.B
Liquid A has a pH of 10,
Liquid B has a pH of 3
Liquid C has a pH of 7
6. Which liquid has the fewest hydrogen ions dissolved
in water?
7. Which liquid has the most hydroxide ions dissolved in
water?
8. Rank the liquids in order from most basic to least
basic.
9. Which liquid has the most hydrogen ions dissolved in
water?
10. In which liquid does the number of hydrogen ions
equal the number of hydroxide ions?
Checking In!
pH Base:
7-14
pH Neutral:
7
pH Acid:
0-7
Answers:
1.A
2.A
3.A>C>B
4.B
5.C
Stoichiometry with Acids/Bases?

Of Course.
Titrations
A common laboratory method of chemistry that is used to
determine the unknown concentration of an identified acid or
base
H2C2O4(q) + 2NaOH(aq)  Na2C2O4(aq) + 2H2O(l)
Oxalic acid,
H2C2O4
Titration Calculations
If 130 mL of 1.0 M HCl is used to titrate 140 mL of
LiOH. What is the molarity of the LiOH used in the
titration?
Titration Calculations
0.03562 L of NaOH is neutralized with 0.0252 L of
0.0998 M HCl by titration.
What is the concentration of the NaOH used?
How to Solve Titrations:

1.
2.
3.
4.
5.
To find the molarity of the acid/base:
Write and balance the chemical equation
Convert volumes to liters
Start with the volume of the known solution (you
know the volume AND molarity). Convert to
moles.
Use the mole-to-mole ratio to convert to moles
of the unknown.
Plug the moles and liters into the molarity
equation to solve for the concentration (M).
Titration
1. Add known solution to
unknown solution to
determine concentration.
2. Phenolphthalein indicator
shows the end point of your
lab (pH 8)
 End
Point
 Desired
pH has been reached
 Equivalence
 Moles
Point
of acid = moles of base
Indicators
Change
colors with a
change in
pH
Indicators
Hints For Lab
The Meniscus
Read “upside down”
Use paper to help see line
Read one digit past what you can see
What is your end point?
The Stopcock
CLOSED
OPEN
Identification
LABEL YOUR BEAKERS
USE PAPER TO SEE COLOR
CHANGE
Acid or Base
and Skin
Severity will vary with concentration, but
BE SAFE, NOT SORRY!!
Rinse skin IMMEDIATELY and call for
Ms. Tenerelli
Standardization of a Base Lab
Partners
Wear goggles and aprons: If I have to tell you once to put
them on you are out with a ZERO!
Leave the buret in holder
You will have to do multiple trials (as many as 10)
We are learning… you are supposed to make mistakes!
If you aren’t sure what to do, ASK
I have a secret tip for how to get 1/4th of a drop…