about bicarbonate is that it is a ‘natural’ substance. Your body in fact normally has moderate amounts of bicarbonate all the time, and that is how the CO 2 produced in your tissues by metabolism is transported to your lungs to be exhaled. In fact, bicarbonate is produced whenever you dissolve carbon dioxide in water, but hydrogen ions are also produced, which makes the solution more acidic. I can show you the simple formula indicating the chemical equilibrium, or perhaps you’d like to ask your son Paul to do it?” They saw that Molly’s breathing was returning to a more normal rate, and breathed a collective sigh of relief. “She’s out of danger now, but we’ll keep a close eye on her for a while yet,” said Dr. Martinez. Part V—Explanations Sarah, however, still curious, asked, “So does that mean when you remove CO 2 from a solution, it becomes less acidic and the pH goes back up?” “Gee, Mrs, Mathews,” replied Dr. Martinez, “you’d make a terrific chemist!” “And that’s why Molly’s breathing was that way? Her body was trying to raise its pH by getting rid of as much CO 2 as it could, even though it didn’t really help much, because the problem was all that aspirin, which she couldn’t get rid of!”
Biochem 107L 4-3 The doctor answered, “Yes, and in medical terminology we call that the difference between metabolic acidosis, which is Molly’s problem—lots of acidic compounds in her bloodstream—and respiratory acidosis, which can occur if too much dissolved CO 2 builds up there.” “But that must mean that in your tissues, where metabolism is going on and resulting in all that CO 2 and water, the pH is lower than in your lungs, where your body is getting rid of CO 2 ! Is that why my leg muscles got so sore after my 10-minute sprint home this afternoon—though I’ve always heard it is from lactic acid buildup?” Dr. Martinez answered, “Well, you’re correct on the first count, and the low pH from the lactic acid, not from CO 2 , is the problem in the second instance—but my pager is going off, and I have to rush over to check on another patient. Molly will be fine, but don’t hesitate to give me a call if you have any further questions—and fix that latch on your medicine cabinet!” Part VI—Questions Go to your Worksheet and answer the questions there regarding Molly, her body’s reaction and the treatment.
Biochem 107L 4-4 LAB 5B: BUFFERS AND TITRATION Objectives: By the end of this lab session, you should be able to: 1. Identify a buffer. 2. Calculate the pH of a buffer solution upon the addition of either a strong acid or base. 3. Calculate the amount of strong base that is required to make a weak acid solution. 4. Predict the pH at which a buffer will be effective based on the pKa of the buffer. 4.Understand balanced neutralization reactions and titration graphs in order to determine the total amount of acid or base in a solution.
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- Fall '07