What appears to happen in the sky during one rotation of Earth? Choose the two correct answers. A. The moon appears to hide the sun. B. The sun appears to move past the moon. C. Constellations appear to move from east to west. D. The sun appears to move from east to west. E. The sun appears to move from west to east. F. Constellations appear to move from west to east.

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.

What element has similar physical and chemical properties as boron.

Acompound has the molecular formula c3h8. which class of organic compounds does it belong to?