Luis is helping his parents paint a border around the walls of a room. He uses a stencil to repeat the same design on each wall to form one long grapevine with a bunch of grapes every foot along its length. What type of chemical reaction does this best model? replacement
decomposition
polymerization
synthesis

Nitric acid can be formed in two steps from the atmospheric gases nitrogen and oxygen, plus hydrogen prepared by reforming natural gas. in the first step, nitrogen and hydrogen react to form ammonia: (g) (g) (g) in the second step, ammonia and oxygen react to form nitric acid and water: (g) (g) (g) (g) calculate the net change in enthalpy for the formation of one mole of nitric acid from nitrogen, hydrogen and oxygen from these reactions. round your answer to the nearest .