An object's shadow was observed and measured at different times of the day. The data was recorded in the chart below. How does the data provide evidence that the sun is changing position in the sky throughout the day?

Classify this reaction: 2al+n2-> aln.

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.

Helium decays to form lithium. which equation correctly describes this decay?