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Physical Science Chapter 23
Acids, Bases and Salts
1
Note: You will not be able to view the videos from the internet version of this presentation. Copyright laws prevent that option.
These and many more like them keep the oceans from being big lakes. What do you think this picture is of?
Close-up view of a salt crystal on a pretzel. Salts are formed in the neutralization reaction that occurs when an acid is mixed with a base.
Intro Video 14.
23-1 Acids and Bases
A. Acids—contains at least one hydrogen atom that can be removed.
B. Properties of acids.1. Taste sour
2. Corrosive and can damage to skin or tissue
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Read page 766.
23-1 Acids and Bases
3. React with an indicator such as litmus paper to produce a predictable color change.
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23-1 Acids and Bases
C. Common acids1. Foods contain acids a. Citrus fruits have citric acid b. Yogurt and butttermilk have
lactic acid c. Vinegar, or acetic acid, is in
pickled foods.5
Read page 767.
This lists the names and formulas of a few acids, their uses, and some properties.
23-1 Acids and Bases
2. The stomach uses hydrochloric acid.3. Four acids are vital to industry.
a. Sulfuric acid is used in car batteries and the manufacturing of fertilizer.
b. Phosphoric acid is used to manufacture detergents, fertilizers and soft drinks.
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23-1 Acids and Bases
c. Nitric acid is used to manufacture fertilizers
and explosives.
d. Steel can be cleaned with hydrochloric acid.
7Natural Acids and Bases 4.
23-1 Acids and Bases
D. Base—a substance that forms hydroxide ions in a water solution; also accepts hydronium ions from acids.
E. Properties of bases1. Many are crystalline solids in pure
undissolved state.8
Read page 768
bases
23-1 Acids and Bases
2. Feel slippery in solution.
3. Strong bases are corrosive.
4. React with indicators to produce predictable color changes; litmus paper turns blue.
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Acid and Bases Properties 2.04
23-1 Acids and Bases
F. Common bases are used in cleaning products, medications, fabrics, and deodorants.
Read page 770.F. Solutions of acids and bases.
1. Acid describes compounds that can be ionized in water to form hydronium ions.
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Read page 769.
23-1 Acids and Bases
2. Base describes compounds that can be ionized in water to form hydronium ions.
3. Solutions of acids and solutions of bases are electric conductors to some extent.
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TA: Recast Section 1 Assessment in groups.
23-2 Strength of Acids and Bases
A.The strength of an acid or base depends on how completely a compound separates into ions when dissolved in water.1.A strong acid ionizes almost completely
in solution.
2.A weak acid only partly ionizes in solution.
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Read pg 772-773
23-2 Strength of Acids and Bases
3. A strong base dissociates completely in solution.4. A weak base does not ionize completely.5. Strong acids and bases conduct more electricity than weak ones.6. Equations for strong acids and bases use a single arrow, indicating ions are formed.
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23-2 Strength of Acids and Bases
7. Equations for weak acids and bases use double arrows pointing in opposite directions, indicating an incomplete reaction.
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23-2 Strength of Acids and Bases
8. Dilute and concentrated are terms to describe the amount of acid or base dissolved.
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Strong and Weak Bases 2.31
23-2 Strength of Acids and Bases
A. pH of a solution. 1. pH is a measure of the
concentration of H+ ions in a solution or how acidic or basic it is.
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Read page 774
The pH scale helps you classify solutions as acidic or basic.
Acid & Bases in Beverages 5.49
This experiment shows how well blood plasma acts as a buffer. A. Adding 1 mL of concentrated HCl to 1 L of salt water changes the pH from 7.4 to 2.0. B. Adding the same amount of concentrated HCl to 1 L of blood plasma changes the pH from 67.4 to 7.2.
23-2 Strength of Acids and Bases
a. pH lower than 7 means acidic.
b. pH greater than 7 means basic.
c. pH exactly 7 indicates a neutral solution.
2. pH is determined using a universal indicator paper or a pH meter.
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23-2 Strength of Acids and Bases
3. Blood contains buffers which keep the pH in the blood balanced at about 7.4.
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Video pH 1.09
Recast questions Section 2 Assessment.
23-3 Salts
A. Neutralization—chemical reaction between an acid and a base taking place in a water solution.
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Read Neutralization 777.
23-3 Salts
B. Salt—compound formed when the negative ions from an acid combine with the positive ions from a base; salts also form when acids react with metals.
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Read Salt Formation pg. 777.
23-3 Salts
1. Salt is essential in many animals.
2. Other salt uses include manufacturing of paint, rubber, glass, soap, detergents, and dry cell batteries.
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Read 778 Salts.
23-3 Salts
C. Titration is used to determine the concentration of an acid or basic solution.
1. A solution of known concentration is the standard solution.
2. An acid/base indicator is added to the unknown solution.
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Read Titration pg 780.
Video
23-3 Salts
3. A color change that persists is the end point.
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TA: M L pg 781
23-3 Salts
D. Soaps are organic salts with polar and nonpolar ends.
1. The nonpolar, hydrocarbon end interacts with oil and dirt.
2. The polar end helps oil and dirt dissolve in water.
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Read pg 782-83 Soaps and Detergents.
Video
23-3 Salts
E. Detergents—form more soluble salts with the ions in hard
water and reduce soap scum; can cause other
environmental problems.
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23-3 Salts
F. Esters come from alcohols that are not bases but have a
hydroxyl group.1. Esters are used in fruit
flavorings and perfumes.
2. Polyesters are synthetic fibers used to make fabrics.
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Read Versatile Esters pg. 784-5.
TA: Recast Section 3 Assessment.
Review for Test
In a titration, the point where the indicator changes color and stays that way is the ____.
endpoint
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Review for Test
In a titration, the solution for which the concentration is known is called the _________.
Standard solution
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Review for Test
H3O+ units are called _________.
Hydronium ions
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Review for Test
In an equation describing the ionization of an acid, double arrows pointing in opposite directions indicate the acid is ______.
neutral
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Review for Test
A substance that produces H+ ions in solution is a(n) _____.
acid
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Review for Test
A substance that produces OH- ions in solution is a(n) ____.
base
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Review for Test
Our blood contains ____, which allow small amounts of acids or bases to be absorbed without harmful effects.
buffers
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Review for Test
Organic substances that change color in the presence of an acid or a base are called _____.
indicators
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Review for Test
A compound formed in solution from the negative ion of an acid and the positive ion of a base is a _____.
salt
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Review for Test
Which of these will not react to form an ester?a. Ethyl alcohol and sodium hydroxideb. sodium chloride and ethyl alcoholc. acetic acid and ethyl alcohol
c
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Review for Test
Name characteristics shared by soap and detergents.
They have long carbon chains; they may be classified as an organic salt; they are used for cleaning. 40
Review for Test
What is the best indicator of the number of hydronium ions in a solution?
The pH
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Review for Test
Antacids work because they _____ excess stomach acid.
Neutralize it.
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Review for Test
A solution with a bitter taste and a slippery feel is most likely ____.
A base
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Review for Test
HCl is the formula for ____.
Hydrochloric acid
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Review for Test
When you wash your hands with soap, you are using a ____.
base
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Review for Test
The terms dilute and concentrated refer to the ___ of a solution.
concentration
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Review for Test
The strength of a base that only partly ionizes in solution would be described as ____.
weak
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Review for Test
A reaction between an acid and a base that produces a salt and water is a _______ reaction.
neutralization
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