science 104- monday october 6 th schedule starter attendance return graded assignments lesson on ph...
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Science 104- Monday October 6th
Schedule• Starter• Attendance•Return graded assignments•Lesson on pH•Memory Questions •Discussion on pH lab
Learning Intentions•To relate acids and bases to the pH scale •To understand that substances in nature have different pH values
Learning Curve
Classroom Routines
• Starters• Vocabulary Quizzes• Class website• Missing Class• Participation
StarterCopy down the following definitions Acid: A substance with a pH of less than 7. Vinegar and lemons are acidic substances with a sour taste. (page 467)Base: A substance with a pH of more than 7. Baking soda is an example of a base with a bitter taste. (page 467)pH: A scale that classifies substances according to their acidity and alkalinity. (page 190)
Word Association
When I say a word write down the first three words that come to mind.
READYSET
WORD: FIREREADY
SET WORD: ACIDS
Acids and Bases
• Acids and bases are two special kinds of chemicals
• Almost all liquids are either acids or bases to some degree.
• Whether a liquid is an acid or a base depends on the ions that are present
• When acids and bases mix they neutralize (cancel) each other
In Our Bodies
• Stomach releases hydrochloric acid to help breakdown food
• Heartburn is when the acid comes up the esophagus
• Stomach is protected by thick lining
• Food exiting the stomach is mixed with strong bases
In Nature
• Bee stings- Injects you with an acid- Causes pain and swelling
• Poison Ivy- Produce a basic substance- Severe irritation occurs
What should you do?
Page 188 Textbook
Apply a basic substance like baking soda
Apply an acidic substance like
vinegar or lemon
In Food
Acids - Sour Taste- Used for flavouring
Bases- Bitter Taste
In The Environment
Acid Rain- Damages buildings- Effects plants- Can change the
acidity of lakes http://www.ecokids.ca/PUB/eco_info/topics/frogs/acid_rain/play_acidlake.cfm
How do we know which is which?
One is an acid, one is a base and one is neutral.
Litmus Paper
Blue Litmus Paper
Red Litmus Paper
Acidic Substance
Turns Red Stays Red
Basic Substance
Stays Blue Turns Blue
Neutral Substance
Stays Blue Stays Red
Examples
• You dip a red litmus paper in a liquid and it stays red. What is your liquid (acid, base, neutral)
• What would you do next?
• What would you see?
pH Scale
pH Scale
How Does It Work
• Is a lemon (pH 2) only slightly more acidic than battery acid (pH 0.2)?
Does this makes?
Every increment is increase by a factor of 10!!
Universal Indicator
Battery Acid 0.2Stomach Acid 1.2Lemon Juice 2.0Vinegar 2.2Apple 3.0Tomato 4.2Rain 5.6Milk 6.6Pure Water 7Human Blood 7.4Baking Soda 8.2Milk of Magnesia 10.5Oven Cleaner 13.9
Homework
Memory Check Questions:Page 193
Questions #8-12
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