In this experiment you will create solutions with different ratios of ethanol and water. what is the mole fraction of ethanol when 10.00 ml of pure ethanol is combined with 2.00 ml of water? the volume of 10 ml of the solution must be measured. what vessel should you use to take this volume? what should be done to prepare the vessel?

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.