4. calculate the energy change that would accompany an electronic transition in a hydrogen atom from n = 2 to n = 3 shell. determine whether radiation is absorbed or emitted during this transition. (rh = 2.18 x10 -18 j)

A175 g lump of molten lead at its melting point (327 c) is placed into 55.0 g of water at 20.0 c. the specific heat of lead is 130.j/kg c and the hf of lead is 20,400 j/kg. when the lead and the water have reached equilibrium, what is the temperature of the mixture?

World class speed skaters can skate a 3,000-m course in about 4 minutes.what is their average speed for this course? a. 12.5 m/sb. 1.33 m/sc. 1.25 m/sd. 13.3 m/s

Often called simply "velocity," this is the velocity of an object at a particular moment in time.