30. Which of the following crystal structures has two 90° axis angles and one angle = 90°? a. cubic
c. monoclinic
b. hexogonal
d. triclinic

A__ is two or more substances that are together in the same place but are not chemically combined

Based on the equation and the information in the table, what is the enthalpy of the reaction?

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.