Two chemical reactions are shown: A. Ca(OH)2 - CaO + H2O
B. 4K + O2 + 2K20
Which statement is true?

A. Both are synthesis reactions
B. Both are decomposition reactions
C. A is a synthesis reaction, and B is a decomposition reaction
D. A is a decomposition reaction, and B is a synthesis 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.

The fact that the total amount of energy in a system remains constant is a(n)

The rate constant for the reaction below is 6.2 x 10−5 mol l−1 s −1. if the initial concentration of a is 0.0500 m, what is its concentration after 115 s?