How many neutrons are there in the following atom?

Determine the percent sulfuric acid by mass of a 1.61 m aqueous solution of h2so4. %

Calculate the number of molecules present in 0.750 mol of mgo.

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