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1. The spectral line of a certain metal occurs at 665 nm ( 6.65×10 -7 m). Calcul

ID: 497560 • Letter: 1

Question

1. The spectral line of a certain metal occurs at 665 nm (6.65×10-7 m). Calculate the energy of one photon of this light

2. What is the wavelength, in nanometers, of light with a frequency of 1.67×1015 Hz?

3.

A mass of 7.75 g carbon monoxide is reacted with 8.04 g hydrogen to form methanol.

CO(g) + 2 H2(g) CH3OH(g)

The reaction is performed in a 5.00 L flask at 85.0 °C and proceeds to completion. What is the partial pressure (in mmHg) of each of the three species following completion of the reaction? What is the total pressure in the flask?

CO =? mmHg

H2 =? mmHg

CH3OH =? mmHg

Total =? mmHg

Explanation / Answer

1)

wavelength = 665 nm = 665 x 10^-9 m

energy E = h C / lamda

              = 6.625 x 10^-34 x 3 x 10^8 / 665 x 10^-9

energy E = 2.99 x 10^-19 J

2)

frequency = 1.67×1015

wavelength = c / v

                  = 3 x 10^8 / 1.67×1015

                  = 1.80 x 10^-7

                  = 179.6 nm