Which of the following is a covalent molecule?
a. beo
b. naci
c. caf2
d. nh4

At 300 mm hg, a gas has a volume of 380 l, what is the volume at standard pressure

Imagine that you push on a large rock. at what point does your effort change the rock’s mechanical energy?

Consider hydrogen in an excited state n = 5n=5 that emits photons to reach the ground state. there are various possible transitions other than straight to the ground state that can occur; for example, it can drop to the n = 3n=3 state followed by the n = 3n=3 to the ground state transition. which of the possible transitions will result in the emission of a photon in the visible region?