Which statement best describes what the density of an object represents?
Density is the mass of an object per unit of
length.
Density is the volume of an object of a
certain mass.
Density is the length of an object for a certain
mass.
Density is the amount of matter in a certain
volume.

Who is better, messi or cristiano, i need this for a chemistry class. asap

Which step in naming unsaturated hydrocarbons is used for alkenes but not alkynes

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?