What test is used to compare soil samples using equal amounts of soil samples (a control and unknown) and placed in varying levels of liquids?
a) titration test
b) ultraviolet test
c) density gradient tube test
d) comparison microscope test

What is the polyatamic ion of thiosulfate

Stage in which a typical star has completely stopped fusion

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.