An iron nail (fe) is placed into a solution of copper(ii) sulfate (cuso4). after some time, the blue color of the copper (ii) sulfate disappears and some copper-colored solid (cu) is found on the surface of the nail. the solution now contains iron (ii) sulfate (feso4), and the container feels warmer than before the reaction.
1. does this reaction absorb or release absorb or release energy? how do you know?
2. what do the color changes indicate?

Crinoids, also known as sea lilies, appear to be sea plants but are not plants at all. crinoids are an echinoderm species which uses anchoring structures called holdfasts to attach themselves to the sea floor. crinoids were most abundant in pennsylvania during the mississippian period, which ranged from 375 to 320 million years ago. fossils of the crinoids shows that during most of this time pennsylvania was that provided favorable conditions for crinoid growth. a) glacial terrain b) a dry and sandy plain c) mostly mountain ranges d) covered by warm, shallow seas