Fundamental properties of matter

Fundamental properties of matter - = pH = -log 10 [H + ];...

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Fundamental properties of matter Aqueous solubility - Ionic compounds are often dissociated in water (Tortora et al. Fig 2.6) - Polar organic compounds also interact with water molecules through hydrogen bonding - Nonpolar organic compounds tend to be hydophobic , and do not readily dissolve in water - Amphipathic compounds may disperse to allow polar (or charged) groups to interact with water while burying hydrophobic groups - Solute concentration is usually expressed as molarity , the weight of solute in grams per litre solution, expressed relative to the solute's molecular weight. Acids, Bases, and pH (Tortora et al. Figs 2.7, 2.8) - Acids generate protons (hydrogen ions, H + ) when dissociated into water = A strong acid (e.g., HCl) is an acid that dissociates almost completely in solution = a weak acid (e.g., acetic acid) is only partially dissociated in water - Bases consume protons when dissociated into water. - pH measures the concentration of protons in aqueous solution
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Unformatted text preview: = pH = -log 10 [H + ]; pure water, with a [H + ] of 10-7 M, has a pH of 7 = Addition of acids decreases pH by contributing protons to the solution = Addition of bases increases pH by removing protons from solution- Buffers are combinations of weak acids and their conjugate bases that tend to minimize the impact of addition or consumption of protons from aqueous solution. Many of the characteristic chemical and physical properties of organic molecules result from the properties of their functional groups (Tortora et al. Table 2.3; in that table, note the use of "R" to refer to the "remainder" of a molecule)- Some of these groups have ionic forms = Carboxyl groups may be be anionic at high pH = Amino gorups may be cationic at low pH- Hydroxy and carbonyl groups participate in extensive hydrogen bonding, both between and within molecules- Sulfhydryl groups are especially in formation of covalent bonds within and between polypeptide chains...
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This note was uploaded on 01/23/2012 for the course MCB MCB2010 taught by Professor Smith during the Fall '09 term at Broward College.

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