Introduction to Acids and Bases Chapter 15 Pages 453-458 A physicist, biologist and a chemist were going to the ocean for the first time. The physicist saw the ocean and was fascinated by the waves. He said he wanted to do some research on the fluid dynamics of the waves and walked into the ocean. Obviously he was drowned and never returned. The biologist said he wanted to do research on the flora and fauna inside the ocean and walked inside the ocean. He too, never returned. The chemist waited for a long time and afterwards, wrote the observation, "The physicist and the biologist are soluble in ocean water".
ACIDS What is the first thing that comes to mind when you hear the term acids?
Watch a short clip about the properties of acids
Properties of Acids Acids have a sour taste Acids change the color of acid-base indicators Acids react with active metals Acids react with bases to produce water and salts Acids are electrolytes- conduct electric currents
Match the acid name with formulas Sulfuric Acid Nitric Acid Phosphoric Acid Hydrochloric Acid Acetic Acid CH3COOH(aq) H3PO4(aq) HCl(aq) HNO3(aq) H2SO4(aq)
Properties of Bases Bases have a bitter taste Bases change the color of acid-base indicators Bases feel slippery Bases react with acids to produce water and salts Bases are electrolytes- conduct electric currents MOST BASES ARE HYDROXIDE COMPOUNDS
Types of Acids and Bases There are several different types of acids and bases Since different chemists discovered different properties of acids and bases, each was recognized by the “type”
Svante Arrhenius Svante August Arrhenius (19 February 1859 – 2 October 1927) was a Swedish scientist, originally a physicist, but often referred to as a chemist, and one of the founders of the science of physical chemistry.
Arrhenius Acids and Bases Arrhenius acid is a substance that increases the concentration of hydrogen ions, H+, when dissolved in water HCl(aq) → H+(aq) + Cl-(aq) Arrhenius base is a substance that increases the concentration of hydroxide ions, OH-, when dissolved in water NaOH(s) → Na+(aq) + OH-(aq)
Strong Acids A strong acid are characterized by ability to dissociate 100% to form H+ (H3O+) 7 strong acids (NEED TO KNOW) H2SO4 (Sulfuric) H2SO4 → H+ +HSO4- HClO4 (Perchloric) HClO4 → H+ +ClO4- HClO3 (Chloric) HClO3 → H+ +ClO3- HNO3 (Nitric) HNO3 → H+ +NO3- HCl (Hydrochloric) HCl → H+ +Cl- HBr (Hydrobromic) HBr → H+ +Br- HI (Hydroiodic) HI → H+ +I-
HINT FOR STRONG ACIDS H2SO4 (Sulfuric) 2 HClO4 (Perchloric) 3 For ternary acids, as long as there is a difference of 2 or more hydrogens, then the acid is strong H2SO4 (Sulfuric) 2 HClO4 (Perchloric) 3 HClO3 (Chloric) 2 HNO3 (Nitric) 2
Strong Bases A strong base is characterized by ability to dissociate 100% to form OH- ions in solution The hydroxides are the only strong bases. LiOH, NaOH, KOH, RbOH, CsOH, Ca(OH)2, Sr(OH)2, Ba(OH)2
Acids-Base Reactions If there is a strong acid and strong base when they react, they undergo a neutralization reaction Acid + Base → Salt + Water HCl(aq) + NaOH(aq) → NaCl(aq) + H2O(l)
Brønsted-Lowry Johannes Nicolaus Brønsted born in Varde (February 22, 1879 – December 17, 1947) was a Danish physical chemist. Thomas Martin Lowry (October 26, 1874 - November 2, 1936) was an English physical chemist
Brønsted-Lowry Brønsted-Lowry acid is a molecule or ion that is a proton donor (H+) HCl (aq) +NH3 (g) → Cl- (aq) + NH4+ (aq) Brønsted-Lowry base is a molecule or ion that is a proton acceptor H2O(l) + NH3 (g) → NH4+ (aq) + OH-(aq)
Acids Base Reactions If there is a transfer of a proton, the remaining ion or molecule can re-accept that proton and can act as a base Thus, the leftover ion is then a conjugate base of that acid
Conjugate base Lets see an example HF(aq) + H2O(l) → F-(aq) + H3O+(aq) Acid conjugate base The fluoride ion is the conjugate base of hydrofluoric acid
Acids Base Reactions If there is a transfer of a proton, the new ion can act as a acid Thus, the new ion formed is then a conjugate acid of that base
Conjugate acid Lets see an example HF(aq) + H2O(l) → F-(aq) + H3O+(aq) Base conjugate acid The water molecule is a Brønsted-Lowry base. It accepts the proton to form H3O+, which is an acid. The hydronium ion is the conjugate acid of water.
Gilbert Lewis Gilbert Newton Lewis (October 23, 1875 - March 23, 1946) was a famous American physical chemist known for the discovery of the covalent bond (see his Lewis dot structures and his 1916 paper "The Atom and the Molecule") and his theory of Lewis acids and bases
Lewis Acids and Bases Lewis acid is an atom, ion or molecule that accepts an electron pair to form a covalent bonds Lewis base is an atom, ion or molecule that donates an electron pair
IMPORTANT!! Overview of types of acids Table 15-6 Acid-Base Systems Type Acid Base Arrhenius H+ or H3O+ producer OH- producer Brønsted-Lowry Proton (H+) donor Proton (H+) acceptor Lewis Electron-pair acceptor Electron-pair donor
Concentration The concentration or strength of a solution is measured by molarity Molarity is the number of moles in one liter of solution
Concentration Convert to grams Convert to mL
Practice What is the molarity of sulfuric acid if there is 3.8 moles dissolved in 2.5 liter?
Try One! You have 3.50 L of solution that contains 90.0 grams of sodium chloride. What is the molarity of the solution? First find the moles and then find the molarity 90.0 g NaCl ÷ 58.442 mole/g= 1.54 moles 1.54 moles NaCl ÷ 3.50 liters=0.440 M Molarity is 0.440 M