Question

8. 0/6 POINTS | PREVIOUS ANSWERS MY NOTES ASK YOUR TEACHER Nitrite ion, NO2, is a preservative for bacon and other foods, but it is potentially carcinogenic. A spectrophotometric determination of NO2 makes use of the following reactions. H0,5-O-NH, + NO3 + 2 H+ — | HO,s-O-NEN + 2 H2O HOS-O-NEN+ O-NH, -Aminonaphthalene HO, S O -N=N-O-NH, + H+ Colored product, ._ 520 nm Here is an abbreviated procedure for the determination. To 50.0 mL of unknown solution containing nitrite is added 1.00 mL of sulfanilic acid solution. After 10 min, 2.00 mL of 1-aminonaphthalene solution and 1.00 mL of buffer are added. 3. After 15 min, the absorbance is read at 520 nm in a 5.00-cm cell. The following solutions were analyzed. 50.0 mL of food extract known to contain no nitrite (that is, a negligible amount); final absorbance = 0.154. 50.0 mL of food extract suspected of containing nitrite; final absorbance - 0.641. Same as B, but with 10.0 L of 7.50x10-3 M NaNO2 added to the 50.0-ml sample; final absorbance = 0.966. (a) Calculate the molar absorptivity, e, of the colored product. Remember that a 5.00-cm cell was used. 25.76X M-1.cm-1 (b) How many micrograms of NO2 were present in 50.0 mL of food extract B? 2.025X

Answer 1

As corrected = 0).641--0.154 - 0:48- 7 Az u 5 0961-0154 = '812 = 6 12 E(64.71526), T = 9.487 Az + 115 216 0.812? 104 LX 7.5/16"= 50mLxy 1 = 2 23410 CM y=1-516*M =(2.256166%0.05) moles-. 0.1125410"molesro, NOO = 46.0055 glmal = (6:11254,46.00556164) è 5.-12xión = 518Mg. AL- Ed = 0.487 = € x(2:254106) x 5 . E= 6, 434104 m'em!