What energy is required for a reaction to occur?

In a laboratory, 1.55mg of an organic compound containing carbon, hydrogen, and oxygen is burned for analysis. this combustion resulted in the formation of 1.45mg of carbon dioxide and .89 mg of water. what is the empirical formula for this compound?

How do i turn 2 s into one in the products

In which block of the periodic table is uranium (u) found? s blockd blockp blockf block