Acids and Bases Definitions of Acids o Arrhenius

Acids and Bases

Definitions of Acids o Arrhenius Acid-any substance that produces hydrogen ions (H+) when dissolved in water. o Bronsted Lowry acid-any substance that donates protons to form hydronium ions (H 3 O+) o Examples of acids: HCl, HNO 3, H 2 SO 4, HC 2 H 3 O 2

Properties of Acids o o o Taste sour React with metals Conduct electricity p. H<7 Turn litmus red Turn phenolphthalein colorless

Definitions of Bases o Arrhenius Base-any substance that produces hydroxide ions (OH-) when dissolved in water. o Bronsted Lowry Base- any substance that accepts protons. o Examples of bases: Na. OH, Ca(OH)2, Mg(OH)2, NH 3

Properties of Bases o o o Taste bitter Feel slippery Conduct electricity p. H>7 Turn litmus blue Turn phenolphthalein pink

General formula for Acid in water: HA (aq) + H 2 O (l) H 3 O+ (aq) + A- (aq)

Na. OH is an example of a(n) 1. Acid 2. Base 3. Neither 10 1 2 3 4 5 6 7 8 9 10 21 22 23 24 25 26 27 28 29 30 11 12 13 14 15 16 17 18 19 20

A substance that is a proton acceptor is a(n) 1. Acid 2. Base 3. neither 10 1 2 3 4 5 6 7 8 9 10 21 22 23 24 25 26 27 28 29 30 11 12 13 14 15 16 17 18 19 20

HCl is an example of a(n) 1. Acid 2. Base 3. Neither 10 1 2 3 4 5 6 7 8 9 10 21 22 23 24 25 26 27 28 29 30 11 12 13 14 15 16 17 18 19 20

Lemon juice is an example of a(n) 1. Acid 2. Base 3. Neither 10 1 2 3 4 5 6 7 8 9 10 21 22 23 24 25 26 27 28 29 30 11 12 13 14 15 16 17 18 19 20

A substance that is a proton donor is an example of a(n) 1. Acid 2. Base 3. Neither 10 1 2 3 4 5 6 7 8 9 10 21 22 23 24 25 26 27 28 29 30 11 12 13 14 15 16 17 18 19 20

Drain cleaner is an example of a(n) 1. Acid 2. Base 3. Neither 10 1 2 3 4 5 6 7 8 9 10 21 22 23 24 25 26 27 28 29 30 11 12 13 14 15 16 17 18 19 20

Vinegar is an example of a(n) 1. Acid 2. Base 3. Neither 10 1 2 3 4 5 6 7 8 9 10 21 22 23 24 25 26 27 28 29 30 11 12 13 14 15 16 17 18 19 20

Water is an example of a(n) 1. Acid 2. Base 3. Neither 10 1 2 3 4 5 6 7 8 9 10 21 22 23 24 25 26 27 28 29 30 11 12 13 14 15 16 17 18 19 20

A substance that turns litmus red is a(n) 1. 2. 3. 4. Acid Base Neither Both 10 1 2 3 4 5 6 7 8 9 10 21 22 23 24 25 26 27 28 29 30 11 12 13 14 15 16 17 18 19 20

A substance that conducts electricity is a(n) 1. 2. 3. 4. Acid Base Neither Both 10 1 2 3 4 5 6 7 8 9 10 21 22 23 24 25 26 27 28 29 30 11 12 13 14 15 16 17 18 19 20

Naming Acids o Binary acids- consist of hydrogen and one other element. o Use the prefix –hydro and change the ending of the element to –ic. o Example: HCl hydrochloric acid HBr hydrobromic acid H 2 S hydrosulfuric acid

Naming acids o Oxyacids-consist of hydrogen, oxygen, and one additional element. o If the polyatomic ion ends in –ate, change the ending to –ic. o If the polyatomic ion ends in –ite, change the ending to –ous. o Example: H 2 SO 4 sulfuric acid (diprotic) H 2 SO 3 sulfurous acid (diprotic) HNO 3 nitric acid (monoprotic) HNO 2 nitrous acid (monoprotic) H 3 PO 4 phosphoric acid (triprotic)

Naming bases o All bases consist of the hydroxide ion and one additional element. o Name the element followed by hydroxide. o Example: Na. OH sodium hydroxide Ca(OH)2 calcium hydroxide Al(OH)3 aluminum hydroxide Fe(OH)3 iron (III) hydroxide

Which of the following is the correct name of HBr? 1. 2. 3. 4. 10 Hydrobromic acid Bromous acid Bromine hydroxide 1 2 3 4 5 6 7 8 9 10 21 22 23 24 25 26 27 28 29 30 11 12 13 14 15 16 17 18 19 20

Which of the following is the correct name of H 2 CO 3? 1. 2. 3. 4. 10 Hydrocarbonic acid Carbonous acid Hydrogen coarbon oxide 1 2 3 4 5 6 7 8 9 10 21 22 23 24 25 26 27 28 29 30 11 12 13 14 15 16 17 18 19 20

Which of the following is the correct name of Ba(OH)2? 1. 2. 3. 4. 10 Hydrobaric acid Barous acid Barium hydroxide 1 2 3 4 5 6 7 8 9 10 21 22 23 24 25 26 27 28 29 30 11 12 13 14 15 16 17 18 19 20

p. H Scale

Calculating p. H o The p. H scale is a logarithmic scale used to quantitatively represent the strength (concentration) of an acid. o The greater the concentration of the hydrogen ion (H+), the stronger the acid and the lower the p. H.

Sample Problems o What is the p. H of a solution in which [H+] = 1 x 10 -2? o p. H = 2 o What is the p. H of a solution in which [H+] = 1 x 10 -6? o p. H = 6 o Which is more concentrated? o p. H=2

p. H and p. OH o The p. OH scale is a logarithmic scale used to quantitatively represent the strength (concentration) of a base. o The greater the concentration of the hydroxide ion (OH-), the stronger the base and the lower the p. OH. o p. OH + p. H = 14

Practice Problems o Calculate the p. H and p. OH of solutions with the following concentrations and classify as acidic, basic, or neutral. a. [OH-] = 1 x 10 -9 b. [H+] = 1 x 10 -7 c. [H+] = 1 x 10 -4 d. [OH-] = 1 x 10 -2

Indicators and p. H o Indicators are substances that change color depending on the concentration of hydrogen ions (H+) in a solution. o Litmus and phenolphthalein are examples of indicators. o Indicators can be used to determine the p. H of a solution. o http: //www. explorelearning. com/

A solution with a p. H of 3 is 10 1. Acidic 2. Basic 3. Neutral 1 2 3 4 5 6 7 8 9 10 21 22 23 24 25 26 27 28 29 30 11 12 13 14 15 16 17 18 19 20

Which of the following is an expected p. H for a sample of lemon juice? 10 1. 2. 3. 4. 3 6 7 10 1 2 3 4 5 6 7 8 9 10 21 22 23 24 25 26 27 28 29 30 11 12 13 14 15 16 17 18 19 20

A substance with a p. H of 12. 7 is a(n) 1. 2. 3. 4. Acid Base Neither Both 10 1 2 3 4 5 6 7 8 9 10 21 22 23 24 25 26 27 28 29 30 11 12 13 14 15 16 17 18 19 20

A solution with a [H+] =1 x 10 -5 has a p. H of 10 1. 2. 3. 4. 1 5 9 14 1 2 3 4 5 6 7 8 9 10 21 22 23 24 25 26 27 28 29 30 11 12 13 14 15 16 17 18 19 20

A solution with a p. H of 8 has a p. OH of 10 1. 2. 3. 4. 2 6 8 14 1 2 3 4 5 6 7 8 9 10 21 22 23 24 25 26 27 28 29 30 11 12 13 14 15 16 17 18 19 20

A solution with a [OH-]=1 x 10 -3 has a [H+] = 10 1. 2. 3. 4. 3 11 1 x 10 -11 1 2 3 4 5 6 7 8 9 10 21 22 23 24 25 26 27 28 29 30 11 12 13 14 15 16 17 18 19 20

Neutralization Reactions o Neutralization reactions occur when acids react with bases and produce a salt and water. o A salt is an ionic compound consisting of the positive ion of the base and the negative ion of the acid. o Example: HCl + Na. OH Na. Cl + H 2 O acid base salt water o If the [H+] = [OH-], the resulting solution will be neutral (p. H=7). o Neutralization reactions are a specific type of double displacement reaction.

What salt is formed? o o o HCl + KOH H 3 PO 4 + Na. OH Ca(OH)2 + H 2 SO 4 Mg(OH)2 + HF HNO 3 + Na. OH

Titration o A titration is a method for determining the concentration of a solution by reacting a known volume of that solution with a solution of known concentration. o The reaction that takes place is a neutralization reaction.

o http: //www. mhhe. com/physsci/chemi stry/animations/chang_7 e_esp/crm 3 s 5_5. swf

Pre-lab: Which is the most effective antacid? o What makes an antacid effective? o How does the antacid affect the acid? o How will you determine which antacid is most effective at neutralizing the stomach acid?