Does the enclosed drawing represent an element, compound, or mixture?

Which of the following is a compound? a. carbon b. oxygen c. hydrogen d. water

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.

Select all that apply. using a value of ksp = 1.8 x 10-2 for the reaction pbcl2 (s) pb+2(aq) + 2cl -(aq). the concentration of the products yield a ksp of 2.1 x 10-2: