Chemistry Honors Problems 1-10

What feature of Bohr's atomic model accounted for the fact that electrons can have only certain energies?

Bohr's model showed that electrons move in circular orbits around the nucleus. The electrons have the energies associated with those orbits

Calculate the energy of a gamma ray photon whose frequency is 5.02 X 10²⁰ Hz

Energy of a photon = hν h = Planck's constant = 6.626 X 10⁻³⁴ J • s E = 5.02 X 10²⁰ Hz X 6.626 X 10⁻³⁴ J • s E = 3.33 X 10⁻¹³ J

What is the difference in energy between a photon of violet light with a frequency of 6.8 X 10¹⁴ Hz and a photon of red light with a frequency of 4.3 X 10¹⁴ Hz

Energy of a photon = hν h = Planck's constant = 6.626 X 10⁻³⁴ J • s E = 6.8 X 10¹⁴ Hz X 6.626 X 10⁻³⁴ J • s for violet E = 4.5 X 10⁻¹⁹ J for violet E = 4.3 X 10¹⁴ Hz X 6.626 X 10⁻³⁴ J • s for red E = 2.8 X 10⁻¹⁹ J for red Diff. = 4.5 X 10⁻¹⁹ J - 2.8 X 10⁻¹⁹ J = 1.7 X 10⁻¹⁹ J

Describe what is happening when an atom emits a photon

The electron is moving from an orbital of higher energy to an orbital of lower energy

What is the energy content of a photon of violet light that has a wavelength of 413 nm?

You have to convert your wavelength, which is given in nm, to meters first. This way your units will cancel out when you work out the problem. You should get 4.13 x 10^ -7m. Then you divide 3.00 x 10^8m/s by 4.13 x 10^ -7m and you get your v, which should be 7.26 x 10^14/s.

Calculate the energy of a photon of ultraviolet light that has a wavelength of 49 nm

c = λν c = 3.00 X 10⁸ m/s (speed of light) λ = 49 nm or 4.9 X 10⁻⁸ c/λ = ν 3.00 X 10⁸ / 4.9 X 10⁻⁸ = ν ν = 6.12 X 10¹⁵ Hz Energy of a photon = hν h = Planck's constant = 6.626 X 10⁻³⁴ J • s ν = 6.12 X 10¹⁵ Hz E = 6.12 X 10¹⁵ Hz X 6.626 X 10⁻³⁴ J • s E = 4.05 X 10⁻¹⁸ J

A helium-neon laser emits light with a wavelength of 633 nanometers (nm). What is the frequency of this light?

c = λν c = 3.00 X 10⁸ m/s (speed of light) λ = 633 nm or 6.33 X 10⁻⁷ c/λ = ν 3.00 X 10⁸ / 6.33 X 10⁻⁷ = ν ν = 4.74 X 10¹⁴ Hz

What is the wavelength of X rays having a frequency of 4.80 X 10¹⁷?

c = λν c = 3.00 X 10⁸ m/s (speed of light) ν = 4.80 X 10¹⁷ Hz c/ν = λ 3.00 X 10⁸ / 4.80 X 10¹⁷ Hz = λ λ = 6.25 X 10⁻¹⁰ m or 0.625 nm

An FM radio station broadcasts at a frequency of 98.5 MHz. What is the wavelength of the station's broadcast signal?

c = λν c = 3.00 X 10⁸ m/s (speed of light) ν = 98.5 X 10⁶ MHz or 9.85 X 10⁷ Hz c/ν = λ 3.00 X 10⁸ / 9.85 X 10⁷ Hz = λ λ = 3.05 X 10⁰ m or 3.05 m

New-generation cordless phones use a 9.00 × 102 MHz frequency and can be operated up to 60.0 m from their base.How many wavelengths of the electromagnetic waves can fit between your ear and a base 60.0 m away?

λ = c/f = (3.00*10^8)/(900*10^6) = 0.333m 60m/0.333m = 180λ where λ is the wavelength.