University:
York University
Course:
SC/BIOL 2021 | Cell Biology
Academic year:

2023
Views:

459

Pages:

3
Author:

Nick T.

Acid-Base Chemistry and Functional Groups issociation of Water •Water is not a completely stable molecule -Small amounts dissociate Clonize) H₂O H+ + OH- Hydrogen ion hydroxide ion. Hydrogen ions do not exist alove, and will join with other water molecules. Reactions look like this: OHO H H₂O (B) H H₂O H OH H HO hydronium ion + 0 H OH hydroxyl ion proton moves from one molecule to the other •lonization of water actually involves 2 water moleals where one water molecule will pick up the hydroge cation or proton and become H₂Ot and the and water modeales I hydrogen will attach to the first H₂O molecule This gives unique properties to water in which we con have acids and bases [H+] = proton Concentration Acid-Base Reactions Acid: Substance that give up protons (donates) Increases CH+3 (concentration) in solution Base: Substance that accepts protons →Decreases [H+] (Concentration) in Solution Acid-Base Reaction: Chemical reaction that involves transfer of protons Weak Acid Very few molecules dissociated (acetic acid, water) Strong Acid: Readily gives up protons (Hydrochloric acid) HCI H+ + CI STRONG ACID - equilibrium lies far to the right. Nothing but protons Technically correct equation HCl +H₂O H3O++cl • Most molecules act as either an acid or a base • Water can be both (it gives up and accepts protons) Measuring Acidity: The PH Scale. [H+] Can vary by a factor of 100 trillion or more -Its Concentration is expressed more conveniently via the PH Scale -Range is 0-14 -compress the range of concentration by employing logs PH = -log[H+] As pl gets bigger [H+] gets smaller Anytime the pH unit changes by I the Concentration of protons Changes by a factor of 10. be its lo based logarithmic [H+]=1×10 M=0.0000001 M →PH-7 [H+] 1×10-6 M = 0.000001 M [H+]-1×10-2 M-O.OIM →PH=6 PH=2