Final Review Day 3

Classifying Chemical Rxns Synthesis Decomposition Single Replacement Double Displacement

Synthesis or Direct Combination In this type of reaction, two or more substances combine to produce a single, more-complex substance. A +B  AB A or B could be an element or compound Example 2CO (g) + O2 (g)2CO2 (g)

Decomposition or Analysis In this type of reaction a single substance is broken down into two or more simpler substances. AB  A + B AB= compound; A, B are elements Example: 2NaCl (l)  2Na(l) + Cl2(g)

Single Replacement Reactions A reaction in which an element replaces a less active element in a compound, setting the replaced element free A + BC  AC + B Example Zn (s) + H2SO4 (aq)  ZnSO4 (aq) + H2 (g) Zinc and Hydrogen switch places!

Double Replacement Reaction A reaction in which two ionic compounds exchange ions to form two different ionic compounds. AB + CD  AD + CB Example AgNO3 (aq) + NaCl (aq)  AgCl (s) + NaNO3 (aq)

LecturePLUS Timberlake Molarity (M) A concentration that expresses the moles of solute in 1 L of solution Molarity (M) = moles of solute 1 liter solution LecturePLUS Timberlake

The pH scale pH is measured On a scale from 0- 14. pH levels from 0-6 is acidic. pH levels from 8-14 is basic. pH of 7 is neutral.

Calculating Molarity of [H+] or [OH-] [H+] [OH-]= Kw Kw is the ion product for water If [H+] increases, then [OH-] decreases to keep Kw constant. At 25 C, Kw has been found by experiment to be 1.0x10-14. This is always true!

The pH of a Solution 1) pH=-log [H+] 3) [H]=10-pH 2) pH + pOH = 14 4) [H] [OH]=1x10-14 Don’t forget: pH < 7 is acidic pH = 7 is neutral (pure water) pH > 7 is basic

What is the hydrogen-ion concentration of a solution with a pH of 8 What is the hydrogen-ion concentration of a solution with a pH of 8.00 at 25 C? pH=-log [H+] 8.00=-log [H+] [H+]=10-pH [H+]=10-8 [H+]=1x10-8 M