Honors Chemistry Practice Test PDF

Honors Chemistry – Practice Test Light and Quantum Theory Some information that you may find useful: Speed of light (c) = 3.0 × 108 m/s E = hν c = λν Planck's constant (h) = 6.626 × 10–34 J⋅s Wavelength = λ Frequency =...

Honors Chemistry – Practice Test Light and Quantum Theory Some information that you may find useful: Speed of light (c) = 3.0 × 108 m/s E = hν c = λν Planck's constant (h) = 6.626 × 10–34 J⋅s Wavelength = λ Frequency = ν hertz (Hz) = cycles/sec For the hydrogen atom ΔE = –2.178 × 10–18 J (1/nf2 – 1/ni2) 1 mole = 6.022 × 1023 1 nano meter (nm) = 10–9 m Size of hydrogen atom = 1 × 10-10 m Multiple Choice: 1. Which of the following statements is (are) TRUE? 1. The product of wavelength and frequency of light is a constant. 2. As the energy increases, the frequency of the radiation decreases. 3. As the wavelength of light increases, the frequency increases. a) 1 only b) 2 only c) 3 only d) 1 and 3 only e) 2 and 3 only 2. The characteristic light spectrum of an element is produced when a) the energy level of the nucleus is increased b) electrons drop back to lower energy levels c) electrons are raised to higher energy levels d) electrons are emitted by an atom. 3. The relationship between the energy of an atom and the electron’s distance from the nucleus is basically a) the greater the energy the farther the electron is from the nucleus. b) the greater the energy the closer the electron is to the nucleus. c) the distance of the electron from the nucleus is unrelated to the atom’s energy. d) electrons of all energies remain the same distance away from the nucleus. 4. According to the quantum theory of light, the separate packets of energy by which the light waves travel are called a) molecules b) protons c) ions d) neutrons e) photons 5. After an electron drops back from the third to the second energy level, the atom is approaching the a) ground state. b) positively charged state. c) excited state. d) negatively charged state. 6. A radio station broadcasts at 105.2 MHz. The wavelength of the signal is _______ m. a) 3.10 b) 2.85 c) 2.90 d) 3.02 e) 3.84 7. Electromagnetic radiation with a wavelength of 531 nm appears as green light to the human eye. The energy of one photon of this light is 3.74 × 10–19 J. Thus, a laser that emits 1.3 × 10–2 J of energy in a pulse of light at this wavelength produces _____________ photons in each pulse. a) 2.9 × 10–17 b) 9.2 × 10–24 c) 1.8 × 1019 d) 3.5 × 1016 e) 6.5 × 1013 8. The n = 2 to n = 6 transition in the Bohr hydrogen atom corresponds to the _________ of a photon with a wavelength of _________ nm. a) emission, 410 b) absorption, 410 c) absorption, 660 d) emission, 94 e) emission, 390 9. When the electron in a hydrogen atom moves from n = 8 to n= 2 light with a wavelength of __________ nm is emitted. a) 657 b) 93.8 c) 411 d) 487 e) 389 10. The frequency of electromagnetic radiation required to promote an electron from n = 2 to n = 4 in a Bohr hydrogen atom is ________ Hz. a) 4.13 × 10–19 b) 6.17 × 1014 c) 5.46 × 10–19 d) 8.22 × 1014 e) 4.13 × 1019 11. A mole of red photons of wavelength 725 nm has ________ kJ of energy. a) 2.74 × 10–19 b) 4.56 × 10–46 c) 6.05 × 10–3 d) 165 e) 227 12. Which of the following contains a set up invalid quantum numbers? a) n = 3; l = 2; ml = -2; ms = -½ b) n = 2; l = 2; ml = -2; ms = -½ c) n = 1; l = 0; ml = 0; ms = -½ d) n = 5; l = 4; ml = -2; ms = +½ Free Response: 1. Rank the following types of electromagnetic radiation (red light, radio, gamma rays) in order of increasing: Energy: Frequency: Wavelength: 2. Palladium has a first ionization energy of 805 kJ/mol. Is a laser with a wavelength of 552 nm capable of ionizing a palladium atom? 3. One of the very bright lines of light emitted by the sun has a frequency of 4.62 × 1014 Hz. What is the wavelength of this light? 4. How long does it take for light to travel from the sun to Jupiter? Jupiter is 778 million kilometers (7.78 × 108 km) from the sun. 5. Light, in the form of photons, is emitted from atoms when the electron falls from a high energy level to a lower energy level. a) What is the energy difference between the n = 5 and the n = 2 principal energy levels in the hydrogen atom?  b) What is the wavelength of light associated with this energy difference? 6. Just as an atom loses energy in the form of a photon when an electron falls from a high energy level to a lower energy level, you can excite an atom by shining a photon of light on the atom. This would “push” the electron up to higher energy levels from lower energy levels. You can even remove an electron completely from a neutral atom by shining a photon with sufficient energy onto a neutral atom. The total energy required to ionize 1 mole of sodium atoms to sodium 1+ ions (i.e. removing one electron from each atom) is 497 kJ. a) Calculate the energy that is required to ionize just one atom of sodium to a sodium 1+ ion. b) Calculate the wavelength of light that would be able to ionize a sodium atom. Can you see this light? Explain briefly. 7. Identify the n and l quantum numbers for the following subshells. Then state the possible values for the ml quantum number. a) 6p b) 3s c) 4d d) 5p