How would a lower angle of insolation affect the maximum temperature of a surface?

What does x represent in the formula for the compound xcl4?

How many moles of carbon dioxide will form if 2.5 moles of c3h8 is burned

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?