What are Acids and Bases?
An Acid and Base are defined in 3 different ways:
Arrhenius
ü defines an ACID as substances that contain ______ions that ionize when dissolved in ______
v Acids that release 1 ionizable hydrogen ion are called ______acids. If 2 ionizable hydrogen ions are released, it is called a ______acid. An example would be sulfuric acid, H2SO4. An acid such as H3PO4 that releases 3 ionizable hydrogen ions is called a ______acid.
ü defines a BASE as a substance that contains ______ions that ionize when dissolved in water.
Bronsted-Lowry
ü defines an ACID as a hydrogen ______. Acids give up hydrogen ions to bases.
HCl + H2O à H3O+ + Cl-1
Acid Base
The HCl gives its H+ to the H2O in the forward reaction.
You Try!
Who is the acid?
HC2H3O2 + H2O à H3O+ + C2H3O2-1
-
ü defines a BASE as a hydrogen ______
NH3 + H2O à NH4+ + OH-1
Base Acid
The H2O gives its H+ to the NH3 in the forward reaction.
Conjugate Acids & Bases
· When an ______loses a H+, it forms its conjugate base. If the reaction were reversed, the conjugate base would pick up a ______and turn back into the original acid. The strength of the conjugate is the opposite of the original...strong acids form weak conjugate bases.
· What is the conjugate acid of HNO3? ______
· When a ______gains an H+, it forms its conjugate acid. If the reaction were reversed, the conjugate acid would ______an H+ and turn back into the original base. The strength of the conjugate is the opposite of the original...strong bases form weak conjugate acids.
· What is the conjugate acid of Cl-1? ______
Lewis
ü defines an ACID as an ______acceptor.
ü defines a BASE as a ______donor.
Properties of Acids
Representative ion / Hydronium ion (H3O+1) or the hydrogen ion ( H+1)Metals react with acids / Form ______gas via a SR reaction.
Mg + HCl à ______
Dilute solutions of weak acids / Taste sour. Think of citric acid found in
______or acetic acid in ______.
Considered an electrolyte b/c / Hydrogen ions are released in solution. The stronger the acid, the more it ionizes. Strong Acids (strong electrolytes) are ______, ______, and ______. Weak acid (weak electrolytes) are ______& ______.
Has a pH less than 7 / Each decrease of one in pH value is a tenfold ______in acid ______.
Red litmus paper stays RED, Blue litmus paper turns RED
Acids neutralize Bases / To produce a ______and water.
HNO3 + Ca(OH)2 à
Properties of Bases
Representative ion / Hydroxide ion (OH-1)Bases can be formed when / Metals react with ______via a SR reaction. Hydrogen gas is also produced.
Na + H2Oà ______
Dilute solutions of weak bases / Feel slippery & taste bitter. Think of ______used in cooking or antacids.
Considered an electrolyte b/c / Hydroxide ions are released in solution. The stronger the base, the more it ionizes. Strong Bases (strong electrolytes) are ______, ______, and ______. Weak bases (weak electrolytes) are ______& ______.
Has a pH greater than 7 / Each increase of one in pH value is a tenfold ______in base ______.
Red litmus paper turns BLUE; blue litmus paper stays BLUE!
Bases neutralize Acids / To form a salt and ______
NaOH + HCl à
Naming Acids: Two Types
Binary Acids
· Naming: “hydro” prefix, followed by nonmetal ion name with last syllable replaced with –ic acid
Ø HCl(aq) : hydro + (chloride - ide + ic acid) à hydrochloric acid
Ø H3N(aq) : hydro + (nitride – ide + ic acid ) à hydronitric acid
You Try!
HBr(aq) ______
H2S(aq) ______
· Writing formulas: place the H+1 in front of the anion and criss-cross to neutralize the charges if necessary.
Hydrofluoric acid ______
hydrophosphoric acid ______
Oxyacids (ternary acids)
· Naming: NO “hydro” prefix, polyatomic ion name followed by –ic acid if ion ends in –ate or –ous acid if ion ends in –ite.
Ø HClO3(aq) : (chlorate - ate + ic acid) à chloric acid
Ø HClO2(aq) : (chlorite – ite + ous acid ) à chlorous acid
You Try!
Ø H2CO3(aq) ______
Ø H2SO4(aq) ______
· Writing formulas: place the H+1 in front of the polyatomic ion and criss-cross to neutralize the charges if necessary. Remember parentheses.
Sulfurous acid ______
Phosphoric acid ______
Acetic acid ______
Naming “Metal Hydroxide” Bases
· Name the metal with the regular element name and the OH ion with hydroxide.
NaOH ______
Fe(OH)3 ______
· Writing formulas: place the metal ion in front and the OH-1 in the back and criss-cross to neutralize the charges if necessary.
Calcium hydroxide ______
Copper(I) hydroxide ______
Self Ionization of Water
H2O(l) + H2O(l) à H3O+ (aq) + OH- (aq)
KW = [H+][OH-]
Ø In a neutral solution, the ______ions equal the hydronium ions. The concentration of H+ = 1.0 X 10-7 M, so the pH = 7
Ø In an acidic solution, hydronium ions are ______than hydroxide ions. [H+] 1.0 X 10-7 M, so the pH < 7
Ø In a basic solution, hydronium ions are +______than hydroxide ions. [H+] < 1.0 X 10-7 M, so the pH > 7
pH
· pH is defined as the power of the hydrogen. It measures the ______of a substance.
1…………………………………..7………………………………….14
Strong Acid Weak Acid N Weak Base Strong Base
pH Of Common Substances
Substance pH
Apples About 3
Orange Juice 3
Grapes About 4
Carrots About 5
Potatoes About 6
Seawater 8-9
Soap 9-10
Milk of Magnesia antacid 10
Household ammonia 11
Household bleach 12
How to Calculate pH, pOH,[OH-] and [H+]
pH = -log[H+] pOH = -log[OH-]
KW = [H+][OH-] pH + pOH = 14
Calculate [H+] and [OH-]
1. Calculate the hydrogen ion concentration if the hydroxide concentration is
1.0 x 10-3 M. Is the solution acidic, basic, or neutral?
2. Calculate the hydroxide concentration if the hydrogen concentration is
1.0 x 10--8 M. Is the solution acidic, basic, or neutral?
Calculate pH and pOH
1. Calculate the pH of a solution with a [H+] of 1.0 x 10-2 M.
2. Calculate the pH of a solution with a [H+] of 3.6 x 10-9 M.
3. Calculate the pH of a solution with a [H+] of .025 M.
4. Calculate the pOH of a solution with a [OH-] of 1.0 x 10-3 M.
5. Calculate the pOH of a solution with a [OH-] of 6.5 x 10-4 M.
6. Calculate the pH of a solution with a [OH-] of 2.6 x 10-2 M
7. Calculate the hydrogen ion concentration of a pH of 2.37
8. Calculate the hydroxide ion concentration of a pOH of 8.45.
9. Calculate the hydrogen ion concentration of a POH of 8.45.
Neutralization
· When and acid and a base are mixed, the ______from the acid and the ______from the base combine to form ______and a salt. A salt is an ______that is formed from the cation of the base and the anion of the acid.
· 1mol of H+1 ions neutralizes 1 mol OH-1 ions to form 1 mol H2O
· a type of ______reaction
Examples
HCl (aq) + NaOH (aq) à NaCl (aq) + HOH (l)
Acid Base Salt Water
You try!
H2SO4 (aq) + 2 KOH (aq) à
Titrations
· a process used to determine the ______of an acid or base in a neutralization reaction.
· Steps to titrating an acid
1. Fill a buret with a known concentration of base. This is called your ______.
2. Take a specific volume of unknown concentration of acid and place in a Erlenmeyer ______. This is called your ______.
3. Add an indicator. An indicator is a substance that turns certain ______in the presence of an acid or base. For example, phenolphthalein turns ______in the presence of a base and remains ______in the presence of an acid.
4. Add the base to the acid ______until the indicator just begins to change color .
5. Record the amount of the base necessary to ______the acid.
· The pH of a solution when the indicator turns color is called the ______. The point at which the hydroxide ions and the hydrogen ions are equal is called the ______point.
· The end point signifies equivalence point but they are not the same.
*****Other common indicators are: bromothymol blue, litmus, and ______
How to Solve a Titration Calculation?
v Mol = M x V
v Moles of Acid must ______moles of Base!
v Steps to solving the problem
1. Use the known volume and concentration of titrant to calculate moles of titrant.
2. Convert moles of titrant to moles of analyte using balanced chemical equation.
3. Use the moles of the analyte to calculate Volume or Molarity depending on what is given.
Examples
1. How many moles of LiOH are needed to exactly neutralize 2.0 moles of H2SO4?
2. How many moles of H2SO4 are needed to exactly neutralize 5.0 moles of
NaOH?
3. If it takes 15.0 mL of 0.40 M NaOH to neutralize 5.0 mL of HCl, what is the
molar concentration of the HCl solution?
4. If it takes 15.0 mL of 0.40 M NaOH to neutralize 5.0 mL of HCl, what is the
molar concentration of the HCl solution?
Titration Graphs
· Show pH changes through the titration process.
· Notice equivalence point is different when different strengths of acids and bases neutralize.