CHEM 104 Lecture Notes - Lecture 18: Hydronium, Ph, Electronegativity
Document Summary
Autoionization: water molecules react to produce aqueous hydrogen ions and aqueous hydroxide ions. * the rxn between water molecules and the hydronium and hydroxide ions is very reactant favored * Applies to pure water and all aqueous solutions. Acid is added = h3o+ ion concentration ([h3o+] > [oh-]) increases. Base is added = h3o+ ion concentration ([h3o+] < [oh-]) decreases. The ph scale ph the negative of the base 10 logarithm (log) of the hydronium ion concentration (expressed in mol/l) ph = log[h3o+] * the negative log is used because it gives a positive ph value for small concentration values. * change of one ph represents a ten-fold change in h3o+ concentration * Log kw = log[h3o+] + ( log[oh-]) = log(1. 0 x 10 14) pkw = ph + poh = 14. 00. Within a group, acidity increases as bond strength increases. Within a period, acidity increases as bond polarity increases.
