Transcript Acid Base - cloudfront.net

ACIDS AND BASES!
Learning Objective: To understand the
difference between acids and bases and how
to test if a solution is an acid or base.
Pg #
Title
Acids and Bases
Standard
5e
Do Now: Answer these questions in your labbook.
Why does lemonade taste sour? Why does
soap feel slippery? What makes cakes rise?
Homework:
Fill out Frayer models
for acids and bases
Agenda:
1. Reading
2. IBE
3. Active Notes
What are we learning today?
5. e. Students know how to determine
whether a solution is acidic, basic, or
neutral.
IBE
• On your IBE sheet…
–Fill in the Pre Lab section
–Make your Hypotheses by filling
out the prediction column in the
table
• Use the droppers to put some liquid in each
well, use the pH paper to test if it is an
acid or a base.
What are Acids and Bases?
• Acid
–any compound that increases the
number of hydronium (H3O+) when
dissolved in water
• Base
–Any compound that increases the
number of hydroxide (OH) when
dissolved in water
What are their properties?
• Acids
– Taste: Sour
– Conduct electricity: YES
– Corrosive: YES
• OTHER: Destroys body parts (skin) and clothing
– Other: Reacts with metals
• Bases
–
–
–
–
Taste: Bitter
Corrosive: YES
Conduct electricity: YES
Other: Slippery feel
What are some Examples?
• Acids
• Bases
– Lemons
– Baking bowder
– Vinegar
– Chalk
– Grapes
– Soap
– Sodas
– Saliva in your mouth
– Car batteries
– Your stomach’s digestive “juices” called
gastric acid
How do we use acids?
• Acids
– Sulfuric acid
• Make paint, and detergent
• In car batteries
– Nitric acid
• In fertilizer
– Hydrochloric acid
• Digestion in your stomach
– Citric acid
• In oranges
How do we use bases?
• Bases
–Sodium hydroxide
• Make soap and paper
–Amonina
• Cleaners and fertilizers
–Antacids
• Treat heartburn
Connection to the IBE
What is pH?
Scientific
Definition
Our Definition
How many
hydronium ions
(H3O+) are in a
solution
How acidic is the
solution.
Meaning, is a
solution acidic, is it
basic, or is it
neutral?
What is the pH scale?
Acidic
Neutral
Basic
DIRECTIONS: Label your pH Scale as seen above
Acidic: -5 to 6
Neutral: 7
Basic: 8-14
You MAY color it in with colored pencils, remember to shade dark to light IF
those colors are in your pencil case. If not, maybe you shouldn’t have RUINED
the materials I bought for the class. Disrespect. 
pH Scale Activity Sort - Materials
• Each student should have 1 colored pH
scale to glue into your notebook.
• Each pair should have one cardstock pH
scale, and 1 bag.
pH Scale Activity Sort – Set Up
1. Take the tabs out of the bag, and
spread them out face up.
2. Count your strips to make sure you
have 15.
REMINDER: Acid are pH less than 7
Bases are pH greater than 7
pH Scale Activity Sort – The Game
1. I will read the clues one at a time.
2. You and your pair should be placing the
tabs into the correct spots on the pH
scale
3. At the end we will see how many you
got right
Clue #1
1) We drink acids when
we are thirsty.
Clue #2
2) Water is pH neutral.
Clue #3
3) This is found in Utah
and it has a concentration
of 1/1,000th for Hydrogen
Ions.
Clue #4
4) The strongest acid is
found in car batteries.
Clue #5
5) The strongest base
unclogs your sink.
Clue #6
6) You may swim in this
very weak base during
vacation.
Clue #7
7) This second strongest
acid is found in your
stomach.
Clue #8
8) You may spit out this
very weak acid.
Clue #9
9) Your favorite soft
drink has 10,000 times
more Hydrogen Ions than
pure water.
Clue #10
10) Ammonia has a
concentration of
1/10,000th for Hydrogen
Ions.
Clue #11
11) Bleach is the second
strongest base.
Clue #12
12) Lemon juice is more
acidic than soft drinks.
Clue #13
13) Coffee is less acidic
than tomato juice.
Clue #14
14) Baking soda is more
basic than sea water.
Clue #15
15) In your bathtub, it
may have this pH as it
goes down the drain.
Take out the pH scale glued into
your notebook.
• Open your notebook and copy
down the examples of each pH
range into your notebook.
HOMEWORK
• Complete the Vocabulary
Foursquare for Acids and
bases.
• I will collect this tomorrow.
What is an Indicator?
• You may be wondering
–How do we know if a solution
is an acid or a base?
–An indicator changes color
in the presence of an acid
or base
Indicator examples
• pH paper
• litmus paper
• indicator solutions (ex. Bromophenol
Blue)
• pH meters
• Cabbage juice
Acid
What happens to
bromophenol blue in
the presence of
each of acids and
bases?
What happens to
litmus paper in the
presence of each of
acids and bases?
Base
Yellow
Darker
Blue
Red
Blue
Indicator LAB!
• Elect one person on you team to be the
gatherer.
• Elect one person on your team to be
your cleaner.
• These are the only students allowed out
of their seats at one time.
Exit Slip
1. Why does lemonade taste sour?
2. If a substance has a high number on the pH
scale then it is a ________________?
1. How do we find out if a substance is an acid or
base?
Exit Slip - Answers
1. Why does lemonade taste sour?
Because it is acidic, and acids taste sour
2. If a substance has a high number on the pH
scale then it is a ________________?
Base, bases have a pH > 7
1. How do we find out if a substance is an acid or
base?
We use an indicator, such as pH paper,
litmus paper, or cabbage juice