When you knock on a door, what causes you to hear a sound? Vibrations that cause bound beams
Vibrations that cause sound waves
Vibrations that cause sound circles
Vibrations that cause sound

B.

Explanation:

the equation that correctly represent the reaction for formation of ammonia is

n2+ 3h2 → 2nh3 (answer d)

1 mole of nitrogen gas (n2) react with 3 moles of hydrogen gas (h2) to form 2 moles of ammonia ( nh3). this is in a process known as haber process were iron is used as a catalyst and reaction take place that a higher temperature and pressure. the process is exothermic hence energy is released.

its first and third is your answer i did the qustion the fourth isnt right