People breathe in oxygen molecules from the air and exhale carbon dioxide molecules. because of this, the air is full of carbon dioxide and oxygen mixed together. what is this an example of?

a.) an increase in entropy

b.) an increase in oxidation reactions

c.) an increase in enthalpy

d.) an increase in evaporation

hellppp pl! for sure who knows the answer

~apex~

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.