Please help me please will mark the brainiest due today at 6:00pm please help

Can someone me with questions 12 and 13 plz.

What is the empirical formula for c4h8o2

Which theory was contradicted by experiments with the photoelectric effect? light spreads out after it passes through a small opening. as soon as light strikes metal, electrons will be ejected. visible light, regardless of color, will cause the ejection of electrons when striking metal. the kinetic energy of ejected electrons depends on the frequency of light that strikes the metal.