Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Introduction to Environmental Engineering, First Edition Richard O. Mines and Laura W. Lackey

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Introduction to Environmental Engineering, First Edition Richard O. Mines and Laura W. Lackey Figure 3.1 Periodic Table.

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Introduction to Environmental Engineering, First Edition Richard O. Mines and Laura W. Lackey Equivalent Weight, EW EW = MW/Z Z = valence or charge g/eq or mg/meq Normality, N N = (mass of material/L or solution)/ EW = number of equivalents/ L of solution N = z X M

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Introduction to Environmental Engineering, First Edition Richard O. Mines and Laura W. Lackey

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Introduction to Environmental Engineering, First Edition Richard O. Mines and Laura W. Lackey Chemical Reactions Types of Reactions 1)Synthesis or combination reactions A + B → C 2)Decomposition reactions AB → A + B 3) Single-replacement reactions A + BC → AC + B 4) Double-replacement reactions AB + CD → AD + BC 5) Combustion reactions C 3 H O 2 → 3 CO H 2 O

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Introduction to Environmental Engineering, First Edition Richard O. Mines and Laura W. Lackey Consider the following reactions: CaO (S) + H 2 O (l) Ca(OH) 2(s) → ← → ← 2 CaO (s) + 3 H 2 ) + 2 PO 4 3- (aq) Ca 3 (PO 4 ) 2(s) + 6 OH - (aq) Yielded by, formed from Reactants, products Subscripts s, l, aq Balanced reversible

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Introduction to Environmental Engineering, First Edition Richard O. Mines and Laura W. Lackey Generalized reaction: aA + bB cC + dD ← → At equilibrium: K = [C] c [D] d [A] a [B] b

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Introduction to Environmental Engineering, First Edition Richard O. Mines and Laura W. Lackey Stoichiometry Law of Conservation of Mass Balancing Equations 1)Insure all products and reactants have proper formula 2)Identify most complicated compound. Asume there is only one of these in the equation. Balance the elementsw in this compound one at a time. 3)Focus initial attention on atoms present in the fewest compounds 4)Continue on a trial and error basis for the remaining compounds. Generally, balance the most prevelant atoms near the end. 5)Remove fractions and simplify to the smallest whole numbers possible.

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Introduction to Environmental Engineering, First Edition Richard O. Mines and Laura W. Lackey Acid-Base Chemistry pH = - log [H + ] pOH = - log[OH - ] pH + pOH = 14 Acid – a compound that donates a hydrogen ion Base – a substance that accepts a proton (hydrogen ion) HA + B - → A - + HB ← Acid Base Base Acid

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Introduction to Environmental Engineering, First Edition Richard O. Mines and Laura W. Lackey Figure 3.2 pH Estimates for common household items.

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Introduction to Environmental Engineering, First Edition Richard O. Mines and Laura W. Lackey Amphoteric compounds can react as either an acid or base H 2 O + H 2 O ← HO - + H 3 O + Acid Base Base Acid H 2 O ← OH - + H + → → K = [OH - ] [H + ] [H 2 O] K w = [OH - ] [H + ] =

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Introduction to Environmental Engineering, First Edition Richard O. Mines and Laura W. Lackey Dissociation Constant HA H + + A - → ← K a = [H + ] [A - ] [HA] BOH B + + OH - K b = [B + ] [OH - ] [BOH]

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Introduction to Environmental Engineering, First Edition Richard O. Mines and Laura W. Lackey pK a = - log K a pK b = -log K b K a X K b = K w =

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Introduction to Environmental Engineering, First Edition Richard O. Mines and Laura W. Lackey

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Introduction to Environmental Engineering, First Edition Richard O. Mines and Laura W. Lackey Carbonates

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Introduction to Environmental Engineering, First Edition Richard O. Mines and Laura W. Lackey

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Introduction to Environmental Engineering, First Edition Richard O. Mines and Laura W. Lackey

Copyright ©2010 by Pearson Education, Inc. Upper Saddle River, New Jersey All rights reserved. Introduction to Environmental Engineering, First Edition Richard O. Mines and Laura W. Lackey