Acids/Bases/Salts Properties

Properties BASES ACIDS electrolytes electrolytes bitter taste sour taste turn litmus red turn litmus blue Feel like burning slippery feel vinegar, soda, apples, citrus fruits ammonia, lye, antacid, baking soda pH more than 7 pH less than 7

Naming Acids are composed of hydrogen (H+) followed by an anion (negative ion). If the acid formula contains oxygen in the anion, such as in H2SO4, it is known as an oxyacid.

3 Rules To Naming Acids If H + anion ending in –ide: Acid name is “hydro_____ic acid” Take the root from the anion name and fill in the blank.

Acid Naming Example Example: HCl Cl is the anion, its name is chloride Name of acid is: hydrochloric acid Example: HF F is the anion, its name is fluoride Name of acid is: hydrofluoric acid

3 Rules To Naming Acids H + anion ending in –ate: Acid name is “_____ic acid” Take the root from the anion name and fill in the blank. “What I ATE was ICky”

Acid Naming Example Example: HNO3 NO3 1- is the anion, its name is nitrate Name of acid is: nitric acid Example: H2CO3 CO3 2- is the anion, its name is carbonate Name of acid is: carbonic acid

Exceptions Sulfate (SO4 2-) Phosphate (PO4 3-) Root is not sulf, but sulfur Sulfuric acid Phosphate (PO4 3-) Root is not phosph, but phosphor Phosphoric acid

3 Rules To Naming Acids H + anion ending in –ite: Acid name is “_____ous acid” Take the root from the anion name and fill in the blank. “Don’t bITE; it’s infectiOUS”

Acid Naming Example Example: HNO2 Example: HClO2 NO2 1- is the anion, its name is nitrite Name of acid is: nitrous acid Example: HClO2 ClO2 1- is the anion, its name is chlorite Name of acid is: chlorous acid

Writing Formulas Just work backwards, using the three rules. You must criss-cross charges, just like with ionic compounds H+ + anion-

Acid Writing Example Hydrobromic acid Acetic acid Phosphorous acid anion is bromide (Br -) formula is HBr Acetic acid anion is acetate (C2H3O2 -) formula is HC2H3O2 Phosphorous acid anion is phosphite (PO33-) formula is H3PO3

Naming Hydroxide bases are composed of a cation (positive ion) followed by hydroxide (OH-). Naming bases is much simpler than naming acids. Name the cation and then add “hydroxide.”

Exception!!!! Memorize: NH3 = ammonia

Base Naming Example NaOH Mg(OH)2 Fe(OH)2 name of base: sodium hydroxide Mg(OH)2 name of base: magnesium hydroxide Fe(OH)2 name of base: iron (II) hydroxide

Writing Formulas Writing base formulas is straightforward. Find the formula for the cation and then add OH -. Remember to criss-cross the formula so that the charges equal out to zero.

Base Writing Example potassium hydroxide calcium hydroxide cation is potassium (K+) formula is KOH calcium hydroxide cation is calcium (Ca 2+) formula is Ca(OH)2 aluminum hydroxide cation is aluminum (Al 3+) formula is Al(OH)3

Electrolytes Solutions that have “free ions” in solution. ***Use solubility rules to determine if a compound will ionize in water*** Those “free ions” conduct electricity. Found in sports drinks because body cells need ions to do work Ex: Sodium/Potassium Pump

Strong Acids Strong because there is a strong attraction between the acid and the water molecule. Every acid molecule ionizes (dissolves)

Strong Acids Prechloric Acid: HClO4 Sulfuric Acid: H2SO4 NEED TO MEMORIZE! Prechloric Acid: HClO4 Sulfuric Acid: H2SO4 Hydriodic Acid: HI Hydrobromic Acid: HBr Hydrochloric Acid: HCl Nitric Acid: HNO3

Strong Acids If it is not listed. it is considered a weak acid. Weak- they remain as molecules, they don’t ionize in water.

Strong Bases Strong because there is a strong attraction between the base and the water molecule. Every base molecule ionizes (dissolves)

Strong Bases NEED TO MEMORIZE! Lithium hydroxide: LiOH Calcium hydroxide: Ca(OH)2 Sodium hydroxide: NaOH Strontium hydroxide: Sr(OH)2 Potassium hydroxide: KOH Barium hydroxide: Ba(OH)2 Magnesium hydroxide: Mg(OH)2

Strong Bases If it is not listed. it is considered a weak base. Weak- they remain as molecules, they don’t ionize in water (And so, do not for electrolyte solutions)

Indicators Chemical dyes that change color as pH changes. Different indicators change colors at different pH levels choose an indicator that will show a color change at the pH that you are interested in. Indicators can be on a strip of paper called pH or litmus paper Other indicators can be added to the solution directly. Some indicators change color more than once and can be added to solutions so that we can see what is happening over time.

pH scale 14 7 INCREASING ACIDITY INCREASING BASICITY NEUTRAL

pH Whether or not a solution is acidic, basic, or neutral depends on the balance of H+ and OH- ions: Neutral: [H+] = [OH-] Acid: [H+] > [OH-] Base: [H+] < [OH-]

pH calculations (#1) pH + pOH = 14 The sum of the pH and the pOH always equals 14. pH + pOH = 14

Example Find the pH, the pOH = 5.3 pH + pOH = 14 pH = 14 - 5.3

pH pH is the negative base 10 logarithm of the hydrogen ion concentration: pH = - log [H+]

pH calculations (#2) pH is the expression of the acidity or alkalinity of a solution in terms of its hydronium ion concentration. pH = - log [H+]

Example Calculate the pH, if the [H+] = 2.4 X 10-6 M pH = - log [H+] = - log(2.4 X 10-6) = -(-5.6) = 5.6

pH calculations (#3) Use an identical equation to calculate pOH. pOH = - log [OH-]

pH calculations (#4) Use the reverse of the equation to calculate the [H+] when pH is known. [H+] =10(-pH)

Example Calculate the [H+], if the pH is 4.71. [H+] = 10(-pH) = 10 ^ (- 4.71) = 1.95 X 10-5 M

pH calculations (#5) Use identical process for [OH-] when pOH is known. [OH-] = 10(-pOH)

Acid/Bases/Salts Neutralization/Titrations

A. Neutralization Chemical reaction between an acid and a base. Products are a salt (ionic compound) and water.

ACID + BASE  SALT + WATER A. Neutralization ACID + BASE  SALT + WATER HCl + NaOH  NaCl + H2O strong strong neutral HC2H3O2 + NaOH  NaC2H3O2 + H2O weak strong basic Salts can be neutral, acidic, or basic. Neutralization does not mean pH = 7.

Neutralization HCl + NaOH  NaCl + H2O H2SO4 + KOH  HNO3 + Ca(OH)2  +1 -1 HCl + NaOH  H2SO4 + KOH  HNO3 + Ca(OH)2  NaCl + H2O Hydrocholoric acid Sodium chloride Water Sodium hydroxide +1 -2 2 K2SO4 + H2O 2 Potassium hydroxide Potassium sulfate Sulfuric acid Water +2 2 -1 Ca(NO3)2 + H2O 2 Nitric acid Calcium hydroxide Calcium nitrate water

B. Titration standard solution unknown solution Titration Analytical method in which a standard solution is used to determine the concentration of an unknown solution.

B. Titration End Point – Equivalence point point at which an indicator changes color during a titration Equivalence point Point at which equal amounts of H3O+ and OH- have been added. when mole ratio exactly equals mole ratio required by reaction Determined by… indicator color change dramatic change in pH

moles H3O+ = moles OH- MV n = MV n B. Titration M: Molarity V: volume n: # of H+ ions in the acid or OH- ions in the base

B. Titration 42.5 mL of 1.3M KOH are required to neutralize 50.0 mL of H2SO4. Find the molarity of H2SO4. H3O+ M = ? V = 50.0 mL n = 2 OH- M = 1.3M V = 42.5 mL n = 1 MV# = MV# M(50.0mL)(2) =(1.3M)(42.5mL)(1) M = 0.55M H2SO4