A gas collected from a reaction has a mass of 1.211 g and occupies a volume of 0.677 L. The temperature in the laboratory is 296 K, and the air pressure is 0.987 atm. Calculate the molar mass of the gas. 23.7 g/mol 44.0 g/mol 58.5 g/mol 82.3 g/mol

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.