A student is developing a model to explain the pattern of seasons on Earth. The student is drawing Earth in different positions around the sun. What details about Earth’s axis should the student include in the drawing?

What is avogadro’s number, and why is it useful

Stage in which a typical star has completely stopped fusion

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.