One of the light waves produced when hydrogen is energized has a wavelength of 4.105 x10^-7 m. What is the frequency of this light?

7.3 x 10¹⁴Hz

Explanation:

Given parameters:

Wavelength  = 4.105 x 10⁻⁷m

Unknown:

Frequency of the light  =?

Solution:

The frequency, wavelength and speed of a wave are related using the expression below;

           C = f λ

C is the speed of light = 3 x 10⁸

f is the frequency

λ is the wavelength

      3 x 10⁸ = f x 4.105 x 10⁻⁷

              f  =   = 7.3 x 10¹⁴Hz

n2(g) + 3h2-> 2nh3(g)   this is the balanced equation

note the mole ratio between n2, h2 and nh3.   it is 1 : 3 : 2   this will be important.

moles n2 present = 28.0 g n2 x 1 mole n2/28 g = 1 mole n2 present

moles h2 present = 25.0 g h2 x 1 mole h2/2 g = 12.5 moles h2 present

based on mole ratio, n2 is limiting in this situation because there is more than enough h2 but not enough n2.

moles nh3 that can be produced = 1 mole n2 x 2 moles nh3/mole n2 = 2 moles nh3 can be produced

grams of nh3 that can be produced = 2 moles nh3 x 17 g/mole = 34 grams of nh3 can be produced

note:   the key to this problem is recognizing that n2 is limiting, and therefore limits how much nh3 can be produced.