Question

O. DATA FROM EXERCISE 8.4 obffr7 A. Ability of Buffers to Stabilize the pll of Solutio L. Enter your data in these spaces 10 drops 12 plt of disáled water: y pli of water + 1 drop HCE pll of water + 1 drop NO pH of buffer: 7.000 pl of buffer+ 1 drep HC pH of baller + 1 drop NaOH pH ofbufer + 3 drops HiC pt of buffer+3 drops NaOH 1 draps of solutions Bxplain your anseres 2Does your data support the rhers hepbise th Efect of Exercise on the Rate of CO, Production Enter your data in these spaces Tese for color change at restySec Time for color change after execise 92SC R 2 Explain your resulsDacqcase C. Role of Carbon Dioside in the Regulation of Vencilaction 1. Enter your data in these spaces Rate of breathing after hypervencilation: Explals your results 331

Answer 1

A 1. a) pH of distilled water - Pure distilled water should be neutral with a pH of 7, but because it absorbs carbon dioxide from the atmosphere, it's actually slightly acidic with a pH of 5.8.

b) pH of water and one drop of HCl - 1 milliliter of hydrochloric acid added to 10 milliliters of pH-neutral water results in a decrease in the concentration of hydrogen ions by one factor of ten. Thus, the pH of the final solution will be one unit higher than the pH of the original hydrochloric acid. If 1 milliliter of hydrochloric acid is added to 100 milliliters of water, the concentration of hydrogen ions decreases by two factors of ten and the pH increases by two units.

c)pH of water and one drop of NAOH - When this solid is added to water, the ions float apart leading to extra OH- ions in the water: NaOH → OH- + Na+. The resulting large concentration of OH- makes the solution more basic and leads to a dramatic increase in the pH.

d) and e) pH of buffer and one drop of HCl and with one drop of NAOH - There is no change in the pH of the buffer when a drop of 2 M HCl is added to 100 mL of this buffer solution. Thus, the pH of the buffer solution is truly "buffered" against the effect of small amounts of acid or base.

f) and g) Sometimes a solution that is technically a buffer does NOT resist changes in pH. This occurs when so much acid or base are added to the buffer that they become the excess reactant.

2. A buffer is a solution that resists changes in pH upon the addition of a small amount of strong acid or strong base. Sometimes a solution that is technically a buffer does NOT resist changes in pH. This occurs when so much acid or base are added to the buffer that they become the excess reactant.