What's the percent composition of (NH4)2SO4

A100-watt light bulb radiates energy at a rate of 100 j/s. (the watt, a unit of power or energy over time, is defined as 1 j/s.) if all of the light emitted has a wavelength of 525 nm , how many photons are emitted per second?

What is the equilibrium constant of aa+bb=cc+dd

Complete each row of the table below by filling in the missing prefix or missing exponent.