What amount of red, green, and blue light is necessary to make black? Explain your reasoning

The bond energy for the van der waals bond between two helium atoms is 7.9×10−4ev. assuming that the average kinetic energy of a helium atom is (3/2)kbt, at what temperature is the average kinetic energy equal to the bond energy between two helium atoms

Calculate the energy required to ionize a hydrogen atom to an excited state where the electron is initially in the n = 5 energy level. report your answer in kilojoules

The table lists the lattice energies of some compounds.compoundlattice energy (kj/mol)lif            –1,036licl            –853naf            –923kf            –821nacl            –786which statement about crystal lattice energy is  best  supported by the information in the table? the lattice energy increases as cations get smaller, as shown by lif and kf.the lattice energy increases as the cations get larger, as shown by lif and licl.the lattice energy decreases as cations get smaller, as shown by nacl and naf.the lattice energy decreases as the cations get smaller, as shown by naf and kf.