Jenny is trying to describe a wave. Which example would be the best description? a toy car hitting a wall and bouncing back
a toy car rear-ending a toy car that then rear-ends another toy car
two toy cars driving parallel to each other at the same speed
two toy cars driving away from each other at the same speed

The formation of a solid, also known as a is an indication of a chemical change. precipitate particulate particle powder

Enzymes affect the reactions in living cells by changing the

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 .