West Valley High School General Chemistry Mr. Mata Acids & Bases Chapter 14.1 West Valley High School General Chemistry Mr. Mata

Standard 5C Students will know the observable properties of acids, bases, & salts.

Essential Question: What are the general properties of acids and bases?

PROPERTIES OF ACIDS General formula of acid is HX. Sour taste; corrosive; contain H +1 (hydrogen ions). Aqueous solutions are electrolytes. Cause indicators to change color: BLUE LITMUS PAPER + ACID -> RED COLOR React with some metals to produce H2(g). React with bases to produce salt & water. pH = 0 to 6.9999 on pH scale. Ex: vinegar, citrus fruits

Properties of Bases General formula XOH (where X is a metal). Taste bitter; corrosive; OH -1 (hydroxide ions). Feel slippery to touch. Cause indicators to change color: RED LITMUS PAPER + BASE -> BLUE COLOR Aqueous solutions are electrolytes. React with acids to produce salt and water. pH = 7.0001 – 14 on pH scale. Ex: ammonia, lye

Neutralization Reaction Acid + Base -> Salt + Water ex: HCl + NaOH -> NaCl + H2O H + 1 ion combines with OH -1 ion -> H2O. Na +1 ion combines with Cl -1 ion -> NaCl. H2O is neutral with pH = 7.000

Arrhenius Acids and Bases Svante Arrhenius (1884) proposed theory of ionization for acids & bases. Definition - Acids release hydrogen ions (H +1). - Bases release hydroxide ions (OH -1).

Arrhenius Acids and Bases Acids may be mono, di, or tri protic. Nitric acid (HNO3) = ? H +1 ion 1 H +1 ion = monoprotic acid Sulfuric acid (H2SO4) = ? H +1 ion 2 H +1 ions = diprotic acid Phosphoric acid (H3PO4) = ? H +1 ion 3 H +1 ions = triprotic acid

Bronsted-Lowry Acids and Bases Bronsted-Lowry acid = H +1 ion donor. Bronsted-Lowry base = H +1 ion acceptor. H +1 Ex: H2O + NH3 -> OH -1 + NH4 +1 acid base

Meaning of pH pH = “power of hydrogen”. Acids have pH from 0 to 6.9999. A neutral solution has a pH of 7.0000 Bases have pH from 7.0001 to 14. pH + pOH = 14 “[ ]” = concentration or molarity [H+ 1] x [OH- 1] = 1 x 10 -14 M

The pH Concept Express large [H+ 1] ion concentrations using smaller numbers. Logrithmic scale (base 10 units). pH = - log [H+ 1] [H+] = 1 x 10 –3 M -> pH = 3 (acidic) [H+] = 1 x 10 –7 M -> pH = 7 (neutral) [H+] = 1 x 10 –11 M -> pH = 11 (basic)

The pH Scale 1 pH unit change = 10x change • pH > 7 basic • pH = 7 neutral • pH < 7 acidic

Measuring pH Variety of different indicators. Indicators are acids or bases that change color with the changing [H+1]. Phenol Red (swimming pools) and phenolphthalein (trace blood). Can use pH meter, litmus paper (red or blue), pH paper.

Chapter 14 SUTW Prompt Describe how acids and bases are organized on the pH scale. Complete a 8 -10 sentence paragraph using the SUTW paragraph format. Hilight using green, yellow, and pink. Due Date: Monday, September 12th, 2016 at the beginning of your regular class.