Which combustion equation violates the law of conservation of matter?

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

Why do lunar and solar eclipse not happen every month

Silver is a white metal that is an excellent conductor. silver tarnishes when exposed to air and light. the density of silver is 10.49 g/cm3. the melting point is 962oc and the boiling point is 2000oc. a chemical property of silver is