bis 2 -9-26 -lec 2

bis 2 -9-26 -lec 2 - for 3 protons. SEE LECTURE PPT Steps...

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9/26/2011 Lecture 2 Weak acid- only partially dissociates. - weak acid titrated with strong base = not a straight line. Buffers- ability of a solution to resist a change in pH is its buffer action . most buffers contain weak acid and its salt. consider - capacity of buffer - how well is it going to work? 1. molar concentration - higher molarity the more you have to add to change the pH 2. ratio of conjugate base to acid **good buffer functions within +/- 1 pH unit of the pKa ( test question) Polyprotic acid- acids capable of ionizing to form more than one proton per molecule of acid Ka1 - most acidic. where H2A loses its first proton to make intermediate ion Ka2- where intermediate ion dissociates and forms second proton and base. Amphoteric ion- the intermediate ion, HA- can ionize backward or forward. H3PO4 is a common polyprotic acid- found in cell and is used as a buffer. it dissociates
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Unformatted text preview: for 3 protons. SEE LECTURE PPT Steps for problem solving: 1. identify aid and base components 2. use henderson-hasslebalch equation, calculate molar ratios of various species present at a particular pH. must use the right pKas Amino Acids - building blocks of proteins. - tetrahedral- C is covalently bonded to 4 diff subs. Side chain called R group, COOH, hydrogen and amino group. 2 properties are evident from tetrahedral structure 1. stereoisomerism due to the tetrahedral carbon - The "C" is asymmetric and the groups ... 2. Acid-base properties. - polyprotic acids. Most amino acids found in proteins are L amino acids, except for glycine - (its not asymmetric. .. so it doesnt have L or D) *** responsible for the structure of the amino acids*** only the R- side group changes. also know the 1- letter abbreviation of the amino acid....
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bis 2 -9-26 -lec 2 - for 3 protons. SEE LECTURE PPT Steps...

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