Arectangle or solid of unknown density is 5 m long two meter high and 4 meters wide the mass of the solid is 300 g what is the volume and density of this problem

Can someone me with questions 15 to 17 plz.

Which statement is usually true about the relationship between activation energy and reaction rates? low activation energy barriers result in low rates. high activation energy barriers result in low rates. low activation energy barriers result in no reaction. high activation energy barriers result in no reaction.

This image is an example of a(n) a) atom. b) compound. c) mixture. d) molecule.