To or more or not chemically combined

The twister and runaway train are two coasters at the same amusement park. both coasters start at the same height. the coaster for the twister is twice the mass of the coaster for the runaway train. which roller coaster has greater gravitational potential energy at the start of the ride?

Calculate the number of kilojoules to warm 125 g of iron from 23.5°c to 78.0°c.

Find the mass, in grams, of 5.00*10^23 molecules of f2