The amplitude of a wave is - the distance between maxima as the wave moves forward in space
- the distance between the maximum and minimum of the wave
- inversely related to the frequency
- The distance between a maximum (or minimum) of a wave from the mean, measured perpendicular from the direction of the wave.

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.

the product of the pressure and volume is also constant