What type of reaction does this equation represent?

2I4O9(s) → 4I2(s) + 9O2(g)

If a plot weight (in g) vs. volume (in ml) for a metal gave the equation y= 13.41x and r^2=0.9981 what is the density of the metal?

If a particle has z = 25 and 23 electrons, what is its charge?

Scientists discovered fossils in several layers of the earth you see here. they found fossils of algae, snails, and clams in layer d. given that information, where do you think they found fossil evidence of simple land plants and amphibians?