Acids & Bases
They are everywhere..
In your food
In your house
EVEN IN YOU!!!!!
Our Goals for ACIDS and Bases
• To determine the difference between Acids & Bases
• Discuss the importance of studying Acids & Bases
• Perform an experiment dealing with Acids & Bases
Key Words
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Acid
Base
H+ Ions
OH-Ions
Litmus Paper
• http://studyjams.scholastic.com/studyjams/jams/science/matte
r/acids-and-bases.htm
• In the
seventeenth
century, the Irish
writer and chemist
Robert Boyle first
labeled
substances as
either acids or
bases.
What is an acid?
• An acid is a solution that has an excess of H+
ions. It comes from the Latin word acidus that
means "sharp" or "sour".
• The more H + ions, the more acidic the
solution.
• What is an ion? Answer left side.
Uses of Acids
• Acetic Acid = Vinegar
• Citric Acid = lemons,
limes, & oranges. It is in
many sour candies
such as lemonhead &
sour patch.
• Ascorbic acid =
Vitamin C which your
body needs to function.
• Sulfuric acid is used in
the production of
fertilizers, steel, paints,
and plastics.
• Car batteries
What is a base?
• A base is a solution
that has an excess of
OH- ions.
• Another word for base
is alkali.
• Bases are substances
that can accept
hydrogen ions
Uses of Bases
• Bases give soaps, ammonia,
and many other cleaning
products some of their useful
properties.
• The OH- ions interact
strongly with certain
substances, such as dirt and
grease.
• Chalk and oven cleaner are
examples of familiar products
that contain bases.
• Your blood is a basic
solution.
Teehan Science 8
• Do Now- What are the ions that make
something acidic?
• What are the ions that make
something basic?
• Homework- Read chapter 13-3
Answer q 1-7
Properties of an Acid
• Tastes Sour
• Conduct Electricity
• Corrosive, which means they
break down certain
substances. Many acids can
corrode fabric, skin, and
paper
• Some acids react strongly
with metals
• Turns blue litmus paper red
Picture from BBC Revision Bites
http://www.bbc.co.uk/schools/ks3bitesize/science/chemistry/acids_b
ases_1.shtml
Will the two metals react the same
with HCl?
Why or why not discuss
Properties of a Base
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Feel Slippery
Taste Bitter
Corrosive
Can conduct
electricity. (Think
alkaline batteries.)
• Do not react with
metals.
• Turns red litmus
paper blue.
https://www.brainpop.com/science/
matterandchemistry/acidsandbases/
• Left Side• Discuss with the person next to you.
Write down 3 examples of acids and 3
examples of bases that you use every
day.
pH Scale
• pH is a measure of how acidic or
basic a solution is.
• The pH scale ranges from 0 to 14.
• The pH scale is logarithmic
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Acidic solutions- pH values below 7
A solution with a pH of 0 is very acidic.
A solution with a pH of 7 is neutral.
Pure water has a pH of 7.
• Basic solutions have pH values
above 7.
pH scale
0-6
Strong acids
lemon juice 2.3
7
battery acid 0 hydrochloric acid 1
8-14
black coffee 5
tomato juice 4.1
grapefruit juice 3
milk 6.6
ammonia 11.9
milk of magnesium 10.5
eggs 8 toothpaste 9.9
distilled water 7
over cleaner 13
Strong bases
bleach 13
soapy water 12
liquid drain cleaner 14
https://www.brainpop.com/scien
ce/matterandchemistry/phscale/
Acid – Base reactions
examples
• Each salt listed in
this table can be
formed by the
reaction between
an acid and a base.
Do Now• Turn on your computer and read all
directions of lab by yourself.
• When you are done, read the
directions again.
• Lab Due Tomorrow, answer questions
with reasons and look things up if you
do not know.
• Unit Test Thursday-last grade MP 2
Acid – Base Reactions
• A reaction
between an acid
and a base is
called
neutralization.
• An acid-base
mixture is not as
acidic or basic as
the individual
starting solutions.
How does a salt form?
• When an acid and a base react, a salt and
water are formed ( products).
HCl + NaOH
Acid + base
NaCl + HOH(water)
salt
+ water
Exit Ticket
• What do you think is the pH level of FairLawn
tap water?
• The pH of a swimming pool must be checked
periodically. Why?
• Is it important for Lakes & Rivers to maintain a
certain pH?
https://www.youtube.com/watch
?v=Ms4v0Ekvyuw
You will have litmus paper and pH test paper,
and pH meters. These are indicators of pH or
whether a substance is an acid or a base.
Litmus paper--(purple ):
determines acid or base
(red or blue)
pH paper --( yellow)
gives you a value on the pH
scale from 0-14
pH scale from 0-14