acids and bases chapter 8 - honors. properties of acids and bases – journal 1 read and highlight...

ACIDS AND BASES

Chapter 8 - Honors

Properties of Acids and Bases – Journal 1

• Read and highlight Sections 8.1-8.4 on the worksheet from the back table. Make vocabulary flashcards for Sections 8.3 & 8.4

• I will be coming around with samples for you to taste. Classify each of the liquids as an Acid, Base or Neutral based on what you learn about the characteristics of acids and bases in your reading.

Acids and Bases

• Acids and Bases are Compounds that have very distinct properties.

HCl + H2O H3O 1+(aq)

+Cl 1-(aq)

NaOH(s) Na 1+(aq) + OH 1-

(aq)

WATERBefore understanding Acids and Bases,

you must understand water.1. It is a polar molecule. Like a

magnet.

+ +- -

WATER1. It is a polar molecule. WHY???Oxygen pulls on the electrons more than

Hydrogen does. Oxygen = Higher ionization energy.

+ +- -

WATERBecause water is POLAR (negative

side and positive side), what types of compounds will it DISSOLVE easily?

CHARGED

+ +- -

Acids• Acids: compounds that IONIZEIONIZE and

produce HYDRONIUM IONS when dissolved in water.

HCl + H20 H3O1+ +Cl1-

• Written also as:

HCl H1+ +Cl1-

AcidsAcidsAcidsAcids

When HCl is put in water, a When HCl is put in water, a Hydronium ion, HHydronium ion, H33OO1+1+ (hydrogen ion, H(hydrogen ion, H1+1+) is ) is

formed.formed.Why might acids be Why might acids be

referred to as “PROTON referred to as “PROTON DONORS”?DONORS”?

When HCl is put in water, a When HCl is put in water, a Hydronium ion, HHydronium ion, H33OO1+1+ (hydrogen ion, H(hydrogen ion, H1+1+) is ) is

formed.formed.Why might acids be Why might acids be

referred to as “PROTON referred to as “PROTON DONORS”?DONORS”?

Acids: Acids: ionizationionizationAcids: Acids: ionizationionization

Acids ARE “PROTON Acids ARE “PROTON DONORS”DONORS”

Acids ARE “PROTON Acids ARE “PROTON DONORS”DONORS”

http://www.learning.gov.sk.ca/branches/elearning/tsl/resources/subject_area/science/chem_30_resources/lesson_8/acids_and_bases.shtml

Characteristics of AcidsCharacteristics of Acids

1.1. Taste SourTaste Sour2.2. React Strongly with Metals and React Strongly with Metals and

Carbonates (in soil and rocks) Carbonates (in soil and rocks) 3.3. Burn skinBurn skin4.4. Conduct electricity in water (electrolyte)Conduct electricity in water (electrolyte)5.5. Turn blue litmus paper redTurn blue litmus paper red

Characteristics of AcidsCharacteristics of Acids

1.1. Taste SourTaste Sour2.2. React Strongly with Metals and React Strongly with Metals and

Carbonates (in soil and rocks) Carbonates (in soil and rocks) 3.3. Burn skinBurn skin4.4. Conduct electricity in water (electrolyte)Conduct electricity in water (electrolyte)5.5. Turn blue litmus paper redTurn blue litmus paper red

AcidsAcidsAcidsAcids

Common Acids

Acetic acid CH3COOH Vinegar

Carbonic acid H2CO3 Carbonated beverages

Hydrochloric acid HCI Digestive juices in stomach

Nitric acid HNO3 Fertilizer production

Phosphoric acid H3PO4 Fertilizer production

Sulfuric acid H2SO4 Car batteries

Bases• Bases: ionic compounds that

DISSOCIATEDISSOCIATE and produce HYDROXIDE IONS when dissolved in water.

•NaOH(s) Na 1+(aq)

+ OH 1-(aq)

BasesBasesBasesBases Bases are Ionic compounds that break apart (dissociate) in water to form a negatively charged hydroxide ion (OH 1-).

Why might bases be referred to as “PROTON ACCEPTORS”?

Bases are Ionic compounds that break apart (dissociate) in water to form a negatively charged hydroxide ion (OH 1-).

Why might bases be referred to as “PROTON ACCEPTORS”?

http://web.umr.edu/~gbert/ANIMATED/Asoly.HTML

BasesBasesBasesBases

Bases ARE “PROTON ACCEPTORS”

Bases ARE “PROTON ACCEPTORS”

http://www.mhhe.com/physsci/chemistry/animations/chang_7e_esp/acm2s2_1.swf

http://www.learning.gov.sk.ca/branches/elearning/tsl/resources/subject_area/science/chem_30_resources/lesson_8/acids_and_bases.shtml

BasesBasesBasesBasesCharacteristics of Bases1.Taste bitter2.Feel Slippery 3.Burn your Skin4.Conduct electricity in water

(electrolyte)5.Turn red litmus paper blue

Characteristics of Bases1.Taste bitter2.Feel Slippery 3.Burn your Skin4.Conduct electricity in water

(electrolyte)5.Turn red litmus paper blue

Common Bases

Aluminum hydroxide Al(OH)3 Deodorant, antacid

Calcium hydroxide Ca(OH)2 Concrete, plaster

Magnesium hydroxide Mg(OH)2 Antacid, laxative

Sodium hydroxide NaOH Drain cleaner, soap production

Strength of Acids and BasesWhich would you say is MORE

acidic: • battery acid • Or milk?

WHY is battery acid MORE ACIDIC?

Strength of Acids and Bases1. MORE hydronium (H(H33O O 1+1+)) ions.2. How many hydronium ions are in

the strong acid? In the weak acid?

Strength of Acids and Bases

1. Chemists use a number scale from 0 to 14 to describe the concentration (amount of) hydronium (H(H33O O 1+1+)) ions in a solution.

2. This is the pH ScalepH Scale.

Strength of Acids and Bases

1.1. The pHThe pH of a solution is a measure of the hydronium ion (H(H33O O 1+1+)) concentration.

Strength of Acids and Bases

1. Neutral substances have a value of 7

2. Their number of hydronium ions equal their number of hydroxide ions.

Strength of Acids and Bases

1. Distilled water is neutral.2. It’s hydronium ions equal it’s

hydroxide ionsThis is because water ionizes

slightly.

Strength of Acids and Bases

1.1. Acids have a pH value of LESS THAN 7Acids have a pH value of LESS THAN 72.2. Bases have a pH value of MORE THAN 7Bases have a pH value of MORE THAN 73.3. Which are the strongest acids and Which are the strongest acids and

bases?bases?4.4. Which are the weakest acids and bases?Which are the weakest acids and bases?

5.5. What is NEUTRAL?What is NEUTRAL?

Acids and Bases - JOURNAL

1.1. Fill in the Identifying Acids Fill in the Identifying Acids and Bases sheet.and Bases sheet.

Strength of Acids and Bases

What is the difference between the strong and the weak, regardless of

concentration?Strong substances IONIZE/DISSOCIATE

COMPLETELY.

Strength of Acids and BasesHow do you get strong and weak acids and bases?

• STRONG ACIDS/BASES COMPLETELY STRONG ACIDS/BASES COMPLETELY IONIZE/DISSOCIATEIONIZE/DISSOCIATE

• HCl + HHCl + H22O O HH33O O ++ + Cl + Cl ––

– Reaction only goes in one direction.Reaction only goes in one direction.• WEAK ACIDS/BASES DO NOT dissociate/ionize WEAK ACIDS/BASES DO NOT dissociate/ionize

completelycompletely• NHNH33 + H + H22O O NH NH44

++ + OH + OH ––

– Reaction goes in both directions. Not all of Reaction goes in both directions. Not all of the compound ionizes.the compound ionizes.

– http://www.mhhe.com/physsci/chemistry/chang7/esp/folder_structure/ac/m2/s1/acm2s1_1.htmhttp://www.mhhe.com/physsci/chemistry/chang7/esp/folder_structure/ac/m2/s1/acm2s1_1.htm

pH H3O1+ concentration H3O1+ concentration

0 1.0 1 x 10 0

1 0.1 1 x 10 -1

2 0.01 1 x 10 -2

3 0.001 1 x 10 -3

4 0.0001 1 x 10 -4

5 0.00001 1 x 10 -5

6 0.000001 1 x 10 -6

7 0.0000001 1 x 10 -7

8 0.00000001 1 x 10 -8

9 0.000000001 1 x 10 -9

10 0.0000000001 1 x 10 -10

11 0.00000000001 1 x 10 -11

12 0.000000000001 1 x 10 -12

13 0.0000000000001 1 x 10 -13

14 0.00000000000001 1 x 10 -14

http://www.purchon.com/chemistry/acids.htm#animation

If you multiplied this number by 100, what would be your chances of finding a hydronium ion in solution?

•100%

•10%

•1%

So, your chances get slimmer as the exponent gets LARGER.

The fewer the H3O 1+, the weaker the acid.

If pH is the measure of hydronium ions, why are acids the lowest numbers?

Strength of Acids and Bases – Journal

Fill in the Acids and Bases Practice Sheet.

Reactions between Acids and Bases• When bases REACT with acids, the process is called NEUTRALIZATION.

Reactions between Acids and Bases• They react to form a salt and

water (& HEAT)Hydrochloric Acid + Sodium Hydroxide

Water + Table Salt

HCl + NaOH H2O + NaCl

Common Common SaltsSalts

Sodium chloride NaCl Food flavoring, preservative

Sodium carbonate Na2CO3 Used to make glass

Potassium chloride KCl Used as a salt substitute to reduce dietary intake of

sodiumPotassium iodide Kl Added to table salt to

prevent iodine deficiency

Magnesium chloride MgCl2 De-icer for roads

Calcium carbonate CaCO3 Chalk, marble floors, and tables

Ammonium nitrate NH4NO3 Fertilizer, cold packs

Acids and Bases and Neutralization

• One of the most important aspects of a living system is the amount of acidity or alkalinity

NEUTRALIZATIONNEUTRALIZATION:Why do we need to know?

NEUTRALIZATIONNEUTRALIZATION:Why do we need to know?

• Control of pH is very important

• Control is accomplished with buffers

• Buffers neutralize small amounts of either an acid or base.

NEUTRALIZATIONNEUTRALIZATION:Why do we need to know?

NEUTRALIZATIONNEUTRALIZATION:Why do we need to know?

Alkalinity – the ability of a stream to neutralize acids.

NEUTRALIZATIONNEUTRALIZATION:Why do we need to know?

NEUTRALIZATIONNEUTRALIZATION:Why do we need to know?

Properties of Acids and Bases – Journal 5

• Come in, take out your homework, Come in, take out your homework, and get your LAB sample.and get your LAB sample.

• Write an equation that shows NEUTRALIZATION. Include the names of the REACTANTS and PRODUCTS.

• What is the range of the pH scale? The range for acids? Bases? Neutral?

• What is the strongest Acid value? Base value? What would be a weak acid? Weak base?