I need somebody who is good at high school chemistry in like 20 minutes. I need help with empirical formulas, molecular formulas and stuff like that

What are the percent by mass of copper in penny lab

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.

The equation picture below shows which type of nuclear reaction u 235 + n x e 134 + sr 100 + 2n