Which of the following is an example of observational scientific investigation? a noting the color of a solution when heated. b drying solid produced by placing it in an oven. c placing test tubes in an ice bath for 15 minutes. d mixing two reactants together in a small beaker.

When an object moves in uniform circular motion, the direction of its acceleration is a) in the same direction as its velocity vector. b) in the opposite direction of its velocity vector c) is directed toward the center of its circular path. d) is directed away from the center of its circular path. e) depends on the speed of the object.

If we relied solely on the nonrenewable resources found in the u.s., which one would we run out of first at current usage levels? a. natural gas b. oil c. uranium d. coal

Arigid tank is divided into two equal parts by a partition. one part of the tank contains 3 kg of compressed liquid water at 400 kpa and 60°c while the other part is evacuated. the partition is now removed, and the water expands to fill the entire tank. determine the entropy change of water during this process, if the final pressure in the tank is 40 kpa. use steam tables.