Mr. Wittmer notices that his classroom is covered in a strange green slime. Avi tells him that coconut juice will get rid of the slime. Mr. Wittmer decides to check this out by spraying half of the classroom with water and coconut juice. He sprays the other half with water. After 3 days of treatment, there is no change in the appearance of the green slime on either half of the room. Identify the:

control group

independent variable

dependent variable

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.