Acids bases salts
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Acids, bases, salts. Unit 9 Notes. Acids. An acid is a substance that produces H + or H 3 O + solution . Properties of acids: 1.   Sour taste 2.   React with certain metals to produce hydrogen gas 3.   React with carbonates and bicarbonates to produce carbon dioxide gas

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Acids bases salts

Acids, bases, salts

Unit 9 Notes


Acids

Acids

  • An acid is a substance that produces H+ or H3O+solution.

  • Properties of acids:

  • 1.  Sour taste

  • 2.  React with certain metals to produce hydrogen gas

  • 3.  React with carbonates and bicarbonates to produce carbon dioxide gas

  • 4. Corrode metals

  • 5. React with bases to form a salt and water

  • 6. pH is less than 7

  • 7. Turns blue litmus paper to red “Blue to Red A-CID”

  • 8. Electrolytes- conduct electricity because of ions


Rules for naming acids 1 acids that do not contain oxygen ha

Rules for naming acids#1: Acids that do not contain oxygenHA

Examples:

Formulanot in waterin water

HClhydrogen chloridehydrochloric acid

H2Shydrogen sulfidehydrosulfuric acid

HCNhydrogen cyanidehydrocyanic acid


Rules for naming acids 2 acids that contain oxygen hao x

Rules for naming acids#2: Acids that contain oxygenHAOx


Examples

Examples:

  • Formulasalt/gasFormulaaqueous

  • HNO2hydrogen nitriteHNO2 (aq)nitrous acid

  • HNO3hydrogen nitrateHNO3 (aq)nitric acid

  • H2SO3hydrogen sulfiteH2SO3 (aq)sulfurous acid

  • H2SO4hydrogen sulfateH2SO4 (aq)sulfuric acid

  • H2CO3hydrogen carbonateH2CO3 (aq)carbonic acid

RULES FOR NAMING ACIDS


Practice problems

PRACTICE PROBLEMS

  • GIVE THE FORMULA FOR THE NAME OR THE NAME FOR THE FORMULA

  • H2SH2SO3 (aq)HF (aq)

  • HClO2HIOHNO2

  • H2SO4 (aq)HI (aq)H2C2O4 (aq)

  • Acetic Acidnitrous acidiodic acid


Common acids and uses

COMMON ACIDS AND USES

  • Acid Formula Where found

  • 1.  Hydrochloric HClstomach, cleaning supplies

  • 2.  SulfuricH2SO4car batteries, fertilizer

  • 3.  NitricHNO3explosives, fertilizer

  • 4.  PhosphoricH3PO4detergents, fertilizers

  • 5.  CarbonicH2CO3soda (carbonated)

  • 6.  AscorbicH2C2H6O6vitamin C (fruits, vegetables)

  • 7.  Acetylsalicylic HOOC-C6H4-OOCCH3aspirin

  • 8.  aceticCH3COOHvinegar


Strong and weak acids

Strong and weak acids

  • The most widely used chemical in the world is sulfuric acid.

  • It can cause severe burns because it is a dehydrating agent.

  • This means that takes all the water out of materials, including skin.

  • A strong acid completely ionizes (breaks apart) in water and releases a lot of H+. Example: sulfuric acid (battery acid)

  • A weak acid only partially breaks down in water, so it doesn’t release much H+. Example: acetic acid (vinegar)


Bases

Bases

  • A base is a substance that produces OH- solution.

  • Properties of bases:

  • Tastes bitter, chalky

  • Are electrolytes

  • Feel soapy, slippery

  • React with acids to form salts and water

  • pH greater than 7

  • Turns red litmus paper to blue “Basic Blue”


Common bases and uses

Common Bases and uses

  • BaseFormula Where found

  • 1.  Sodium hydroxideNaOHsoap, lye, drain cleaner

  • 2.  Potassium hydroxideKOHliquid soap

  • 3.  Barium hydroxideBa(OH)2stabilizer for plastics

  • 4.  Magnesium hydroxideMg(OH)2laxative, antacid

  • 5.  Calcium hydroxideCa(OH)2mortar, plaster, lime

  • 6.  Aluminum hydroxideAl(OH)3deodorant, antacid

  • 7. AmmoniaNH3cleaners, fertilizer, rayon, nylon


Strong and weak bases

Strong and weak bases

  • A strong base completely dissociates (breaks apart) in solution and releases a lot of OH-. Example: sodium hydroxide

  • A weak base does not completely break apart in solution and does not release as much OH-. Example: aluminum hydroxide


Acids bases salts

pH

  • There are many ways to consider acids and bases. One of these is pH.

  • [H+] is critical in many chemical reactions.

  • A quick method of denoting [H+] is via pH.

  • By definition pH = -log [H+], [H+] = 10-pH

  • The pH scale, similar to the Richter scale, describes a wide range of values

  • An earthquake of “6” is 10x as violent as a “5”

  • Thus, the pH scale condenses possible values of [H+] to a 14 point scale

  • Also, it’s easier to say pH = 7 vs. [H+] = 1 x 10-7


Acids bases salts

pH

  • The pH scale is a way of expressing the strength of acids and bases

  • Instead of using very small numbers, we just use the NEGATIVE power of 10 on the Molarity of the H+ (or OH-) ion.

  • pH < 7 = acid

  • pH > 7 = base

  • pH = 7 = neutral


Acids bases salts

pH

  • Indicators: substance that change color in the presence of acids and bases

  • Example: bromthymol blue- yellow acid/ blue base/ green neutral

  • phenolthalein- clear acid/ pink base/ light pink neutral

  • phenol red- yellow acid/ pink base/ peach neutral

  • methyl orange- red acid/ yellow base/ orange neutral


P h calculations

pH calculations

  • Kw = [H+][OH−] = 1 x 10-14

  • pH + pOH = 14

  • pH = - log [H+] and pOH = - log [OH-]

  • (The [ ] means Molarity of H+)

  • Example: If [H+] = 1 x 10-10

  • pH = - log (1 x 10-10)

  •  pH = - (- 10) 

  •  pH = 10


P h calculations1

pH calculations

  • 1. If [H+] = 1 X 10-5

  • pH = - log (1 x 10-5)

  •  pH =

  • 2. If the molarity of H+ in a solution is x10 -4,what is the pH?


P h calculations2

pH calculations

  • Calculating [H+]

  • 1. If the pH is 2 what is the [H+]

  • 10 -pH = [H+]

  • [H+] =

  • 2. If the pH is 7 what is the [H+]?


P h calculations3

pH calculations

  • Calculating pOH

  • If [OH-] is 1 x 10 –9

  • pOH = -log (1 x 10 –9)

  • pOH=


P h calculations4

pH calculations

  • Calculating [OH-]

  • 1. If the pOH is 3, what is the [OH-]?

  • [OH-] = 10 –pOH

  • 2. If the pH is 8, what is the [OH-]?

  • pOH + pH = or [H+] + [OH-] = 1x10-14

  • pOH=

  • [OH-] = 10-pOH


Neutralization

Neutralization

  • If you want to neutralize an acid or base, you add a buffer.

  • Buffers are acids, bases, or salts that are mixed with acids or bases to make their pH closer to 7.

  • If you want to neutralize an acid, your buffer must be a base.

  • If you want to neutralize a base, your buffer must be an acid.

  • Buffers in your body help keep your blood’s pH at 7.4. This is necessary because most of your food contains acids.


Neutralization1

Neutralization

  • Neutralization is a chemical reaction between an acid and a base.

  • H+ from the acid combine with the OH- from the base to form water.

  • Metals from the base combine with the nonmetals from the acid to form a salt.

  • Example:

  • HCl + NaOHNaCl + H2O

  • Most salts are formed with a metal and a nonmetal other than oxygen.

  • Some salts are formed with a metal and a polyatomic ion.


Common salts

Common Salts

  • Salt formula uses

  • 1. Sodium chlorideNaClfood preparation

  • 2. Sodium bicarbonateNaHCO3baking soda

  • 3. Calcium carbonateCaCO3chalk

  • 4. Ammonium chlorideNH4Clbatteries

  • 5. Sodium phosphateNa3PO4detergents


Acid rain

Acid rain

  • Unpolluted rain typically has a pH value of 5.6, which is acidic, but not harmful.Any rain that is below 5.6 is considered acid rain.

  • Acid rain can:

  • 1. Dissolve marble in buildings and statues

  • 2. Corrode metal (buildings, cars)

  • 3. Kill plankton (then fish die)

  • Ways acid rain can occur:

  • 1. Burning coal releases sulfur sulfur combines with water in the air  sulfuric acid forms

  • 2. Car exhaust releases nitrogen oxide  combines with water  nitric acid forms

  • Ways to prevent acid rain:

  • 1. “scrubbers” in smoke stacks

  • 2. Nuclear power

  • 3. Cleaner fuel


Soaps detergents and esters

Soaps, detergents, and esters

  • Soaps are organic salts. This means they contain carbon.

  • Soaps are made by reacting fats or oils with sodium hydroxide or potassium hydroxide.

  • Soaps made with NaOH are solids.Soaps made with KOH are liquids. Another product of this reaction is glycerin which is used in lotion.

  • The process of making soap is called saponification.


Soaps detergents and esters1

Soaps, detergents, and esters

  • Detergents are similar to soap, but do not form soap scum which is a precipitate that forms when soap is used in hard water (lots of minerals). This is why most laundry products are detergents , not soaps.

  • An ester is an organic compound formed by the reaction of an organic acid with an alcohol. Estersare responsible for the odors and flavors of flowers, fruits, and other foods. Esters are added to jello and candy to give the flavors of strawberry, banana, or apple.

  • Organic acids are also used to make polyester fibers.


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