2nf3 + 225 kj -> n2 + 3f2 is it exothermic or endothermic

How many moles does 80.0 h2o respresent

What do many bases have in common? apex chemistry sem 2

Which of the following statements is true? a. most heat energy is easily recovered and used for useful actions. b. friction causes molecules to vibrate more slowly. burning air and gasoline in an c. engine changes chemical energy into mechanical energy. it is impossible to d. change mechanical energy into mechanical energy.