Can someone help tutor me on empirical formula, Molecular Formula and Limiting Regent

Which step in naming unsaturated hydrocarbons is used for alkenes but not alkynes

Analyze how limestone is weathered and identify the features that are formed as a result of this dissolution

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.