+

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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