What’s the mass of Ca(NO3)2 need to make 981.46 g of solution if we want 64.46% solution.

How manyatoms of mercury are in 1.4214e+1 ml sample

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

Which of the following is a physical change? a.burning a piece of wood b.sawing a piece of wood in half c.rust forming on an iron fence d.a copper roof changing color from orange to green