In the oxidation of pyruvate to acetyl coa, one carbon atom is released as co2. however, the oxidation of the remaining two carbon atoms—in acetate—to co2 requires a complex, eight-step pathway—the citric acid cycle. consider four possible explanations for why the last two carbons in acetate are converted to co2 in a complex cyclic pathway rather than through a simple, linear reaction.

The content of manganese (mn) in steel was determined spectrophotometrically and with the use of the standard addition method. an unknown sample of mn from a digested steel sample gave an absorbance of 0.185 when analyzed spectrophotometrically. when 5.00 ml of solution containing 95.5 ppm mn was added to 50.0 ml of the unknown steel solution (digested sample), the absorbance was 0.248. calculate the concentration, in parts-per-million (ppm), of mn in the digested steel sample solution.