If a piece of magnesium with a mass of 2.76 grams is added to a solution of hydrochloric acid (HCI), how many grams of hydrogen gas will be produced with excess magnesium chloride? dimensional analysis plz

Urea, co(nh2)2, is manufactured on a large scale for use in producing urea-formaldehyde plastics and as a fertilizer. what is the maximum mass of urea that can be manufactured from the co2 produced by combustion of 1.00 x 104 grams of co2?

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

The identities of substances are the same before and after which type of change