A 315 g sample of sodium-24 decays to 13.0 g of sodium-24 within 60.0 h. What is the half-life of this radioactive isotope?

Aroller coaster car is traveling down a track at 22 m/s. the car has a mass of 2000 kg. what is the kinetic energy of the car? a) 22,000 j b) 968,000 j c) 484,000 j d) 44,000 j

What is the molar mass of a gas that has density of 2.054 g/l

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