Why is water water and not dirt and why is air also water?

The graph above shows how the price of cell phones varies with the demand quantity. the equilibrium price for cell phones is where both supply and demand quantities equal $100, 5,000 5,000, $100

What is avogadro’s number, and why is it useful

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