+
Acids and Bases
+Examples of Acids?
+Examples of Acids
lemon, vinegar, grapefruit. pop
Lactic Acid found in your muscles
Some animals use acid to deter predatorseg. Scorpions spray acetic acid from their glands when frightened.
+What is an Acid?
A substance that produces hydrogen ions when dissolved in water.
Acid + Water --> H+ ions + other ions
Common properties: Taste sour Corrosive React with metals
+Examples of Bases?
+Examples of Bases
Some common bases areSoap, eggs, baking soda, antacidsHow do these feel?
Lidocaine (local anesthetic used at the dentist)
Draino
+What is a Base?
A substance that produces hydroxide (OH–) ions when dissolved in water.
Base + Water --> OH– ions + other ions
Common properties: Taste bitter Feels slippery
+Mixing Acids and Bases
When we mix acids and bases, this is called a neutralization reaction
Acid + Base --> water + salts H+ (aq) + OH– (aq)
+Can you have stronger acids than others?
Is lemon juice a stronger acid than pop?
Can we measure this?
+pH Scale
A numeric scale that is used for identifying if a solution is acidic, basic, or neutral Typically ranges from 0 to 14
Acidic Solution: pH < 7 Lemon juice pH = 2 Tomato juice pH = 4
Basic Solution: pH > 7 Eggs pH = 8 Soap pH = 10
Neutral Solution: pH = 7 Pure Water
+Identifying Acids and Bases
Acid-base Indicators: a chemical that is a characteristic colour when in the presence of an acid or a base
Example: Red and Blue Litmus Red Litmus: Stays red in acid, but turns blue
in base Blue Litmus: Stays blue in base, but turns
red in acid
+Identifying Acids and Bases
Phenolphthalein Colourless from pH of 0 to 8, and then pink from pH 8 to 14.
Universal Indicator Different colours at different pH values
+Properties of Acids and Bases
Property Acid Base
Taste (CAUTION: Never do this in the lab)
Sour Bitter
Touch (CAUTION: Never do this in the lab)
Can be corrosive SlipperyCan be corrosive
Production of Ions Hydrogen ion H+ (aq)
Hydroxide ion OH– (aq)
Reaction with some metals
Reacts (and corrodes) them
No reaction
Electrical Conductivity yes yes
Litmus indicator test Blue litmus turns red Red litmus turns blue
pH Less than 7 (<7) Greater than 7 (>7)
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https://www.youtube.com/watch?v=ujkuW-0cpNw
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