Acids, Bases, and SaltsChapter 8

Students Will Be Able To: Compare and contrast acids and bases

and identify the characteristics they have. List some common examples of acids and

bases. Describe the ionization of strong acids in

water and the dissociation of strong bases in water.

Acids Is any compound that increases the

number of hydronium ions (H3O+) when dissolved in waterIncludes citric fruits (limes, lemons), dill

pickles, apples, and grapes When acids dissolve in water, they ionize

Process of forming ionsThose that ionize are able to conduct

electricity

Acids Acids get their sour taste from hydronium

ions Can be identified using an indicator

An indicator is a compound that changes color depending on the pH of a solution or substance

Blue litmus paper turns red in the presence of an acid

Strong vs. Weak Acids Strong acids ionize completely while weak

acids do not Strong acids conduct electricity good while

weak acids do notStrong acids are good electrolytes

because they have as many H3O+ as they possibly canElectrolytes are substances that

dissolves in water and are capable of conducting electric current

http://rds.yahoo.com/_ylt=A0WTbx7SY9FMo0gAHGqjzbkF/SIG=13kja4g9c/EXP=1288877394/**http:/www.ltcconline.net/stevenson/2008CHM101Fall/CHM101LectureNotes20081022_files/image013.jpg

Examples of Strong and Weak Acids Some examples of strong acids

Hydrochloric acid, HClpresent in your stomach

Sulfuric acid, H2SO4car batteries; the most-used industrial

chemicalNitric acid, HNO3

used in manufacturing fertilizers and explosives

Some examples of weak acidsAcetic acid, CH3COOH

the acid in vinegarFormic acid, HCOOH

the acid in stinging antsCitric acid, H3C6H5O7

the acid in citrus fruits

Use of Acids Acids are used in many manufacturing

processes They are also needed by living organisms

Care should be taken when using either weak or strong acids

Bases

Is any compound that increases the number of hydroxide ions (OH-) when dissolved in water

Have a bitter, soapy tasteBasic solutions tend to feel slipperyAlso contain ions and are capable of

conducting electricityAre identified using red litmus paper

Turns blue in the presence of a base

Strong vs. Weak Bases Strong bases contain a metal ion and a

hydroxide ion that ionizes completely in waterAlso known as metal hydroxidesAre able to conduct electricity well

Therefore, strong bases are good electrolytes

Strong bases often are not soluble in water

Strong vs. Weak Bases Weak bases do not ionize completely in

water to form hydroxide ions

Care with Bases Bases in their concentrated form are more

dangerous than acids Make sure care is taken when working

with bases

Students Will Be Able To:• Describe how to name acids.• Write formulas for acids.

Naming Acids Naming acids depend on whether or not

the acid contains oxygen in the anion All acids have the same cation (hydrogen)

so there is no need to name it

Naming Acids Without Oxygen The acid name comes from the root name

of the anion name The prefix hydro- and the suffix -ic are

then added to the root name of the anion Examples:

HCl, which contains the anion chloride, is called hydrochloric acid

HCN, which contains the anion cyanide, is called hydrocyanic acid

Naming Acids With Oxygen

Suffixes are used based on the ending of the original name of the oxyanion.

If the name of the polyatomic anion ended with -ate, change it to -ic for the acid and if it ended with -ite, change it to -ous in the acid

Examples:HNO3, which contains the polyatomic

ion nitrate, is called nitric acidHNO2, which contains the polyatomic

ion nitrite, is called nitrous acid

Writing Formulas Convert the name to a formula

Determine the anion and add an “H” per negative chargeAssume that hydrogen, H, has a +1

charge in the compound, even though acids are usually made of non-metals, and therefore covalent

For examplesulfur-ic acid contains a sulfate ion2 H+  +  SO4

2-  = H2SO4

Students Will Be Able To:• Determine the meaning of pH.• Examine the relationship between pH and

acid or base strength.• Identify a neutralization reaction.• Describe the importance of titrations while

working with acids and bases.• Determine what a salt is and how it forms.• Compare and contrast soaps and

detergents.

pH Is a value used to express the acidity of

alkalinity of a solution Corresponds to the concentration of

hydronium and hydroxide ions

pH Scale Ranges from 0 to 14

Acids0 to 7 (strong 0-3; weak 4-7)

Bases7-14 (strong 11-14; weak 7-10)

Neutral7

Differences in Acidity Small differences in pH mean larger

differences in the hydronium ion concentration

Determining pH pH can be determined using several

indicators that change color at different pH values

pH can also be measured using a pH meterMeasures the amount of electric current

being created by the movement of the ions in the solution

http://rds.yahoo.com/_ylt=A0WTb_zEatFMJwIAvtijzbkF/SIG=133qge1fe/EXP=1288879172/**http:/jchemed.chem.wisc.edu/jcesoft/cca/CCA3/STILLS/ENDO2/ENDO3/64JPG48/28.JPG

Acid- Base Reactions A reaction between an acid and a base is

known as a neutralization reaction Neutralization is an ionic reaction

Acid- Base Reactions Neutralization reactions tend to form salts

and water Not all neutralization reactions produce

neutral solutionsDepends on

Amount of acids and bases that are combined

Whether the acids and bases are weak or strong

Titrations It is a neutralization reaction in which the

known concentration of one solution is used to determine the unknown concentration of another solution

Salts Salt can be almost any combination of

cations and anions Common table salt contains sodium

chloride, NaCl, which is a salt that is formed from the reaction of hydrochloric acid with sodium hydroxide

Salts are useful substances, and are all around us Examples

sodium hydrogen carbonate, baking soda silver bromide and silver iodide, in photographic film barium sulfate, sometimes used in taking X rays calcium carbonate, in chalk, limestone, and marble

Soaps Works with water to clean objects Are able to dissolve in oil and water Are made by reacting animal fats or

vegetable oils with a solution of sodium hydroxide or potassium hydroxide

Detergents Are used instead of soap to wash clothes

and dishesSoap does not work well with hard

water- leaves behind soap scum Are made of sodium, potassium, or

ammonia salts with fatty acids

Bleach and Disinfectants A disinfectant is a substance that kills

bacteria and viruses Bleach is an example of a disinfectant

It is a basic solution

Antacids Are weak bases that neutralize stomach

acid