Chapter 8 part 2

Chapter 8 part 2 - Ozone, O3, protects Earths inhabitants...

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1 Ozone, O 3 , protects Earth’s inhabitants from the harmful effects of ultraviolet light arriving from the sun. This shielding is a maximum for UV light having a wavelength of 295 nm. What is the frequency in hertz of this light? Recall: speed of light = frequency x wavelength Recall: 1 m = 10 9 nm Recall: c = 3.00 x 10 8 m/s Planck proposed that the vibrating atoms in a heated solid could absorb or emit electromagnetic energy only in discrete amounts. The smallest amount of energy, a quantum, is given by: E = hv as Planck’s constant, h, has a value of 6.626 X 10 -34 J s. Planck’s quantum hypothesis states that energy can be absorbed or emitted only as a quantum or as whole multiples of a quantum, thereby making variations discontinuous, changes can only occur in discrete amounts. PLANCK’S CONSTANT
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2 Calculate the energy in joules of a photon of green light having a wavelength of 560 nm. E = hv H = 6.626 X 10-34 J s v = ? E = ? Hmmmmm…what to do next? Bohr’s Hydrogen Atom • Each specified energy value is called an energy level of the atom E n = -B/n 2 n is an integer, and B is a constant which equals 2.179 X 10 -18 J – The energy is zero when the electron is located infinitely far from nucleus – The negative sign represents the forces of attraction The Bohr Model
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3 Bohr Explains Line Spectra Bohr’s equation is most useful in determining the energy change ( Δ E level ) that accompanies the leap of an electron from one energy level
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Chapter 8 part 2 - Ozone, O3, protects Earths inhabitants...

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