What is the temperature at which a substance changes from a liquid to a gas

Which orbitals form a pi bond? a. the s orbital and three p orbitals b. the s orbital and two p orbitals c. overlapping p orbitals d. overlapping hybrid orbitals

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.

If 16.00g of hydrogen gas reacts with 126.73g of oxygen, how many grams of water are yielded? (both reactants are completely consumed in the reaction.)