In what ways could the smokestacks and the trucks cause pollution in the air?

What is the mass of 0.46 mil of mgcl2

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?

Calculate the percent composition by mass of each element in al(oh)3. use at least three significant figures.