HW1answers pg4 - length? Correct answer: 450 . 661 J....

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
? gal day = 155 mL min × 1 L 1000 mL × 1 gal 3 . 785 L × 60 min 1 hr × 24 hr 1 day = 58 . 9 gal day 017 (part 1 of 1) 10 points The wavelength of molten iron can be esti- mated by using Wien’s law. If the melting point of iron is 1540 C, what will be the wave- length (in nanometers) corresponding to max- imum intensity when a piece of iron melts? 1. 1288 nm 2. 1345 nm 3. 1588 nm correct 4. 1188 nm 5. 1418 nm Explanation: T = 1540 C + 273 = 1813 K By Wien’s law, T λ max = 1 5 c 2 c 2 = 1 . 44 × 10 - 2 K · m T λ max = 2 . 88 × 10 - 3 K · m λ max = 2 . 88 × 10 - 3 K · m T = 2 . 88 × 10 - 3 K · m 1813 K = 1 . 58853 × 10 - 6 m · 10 9 nm 1 m = 1588 . 53 nm 018 (part 1 of 3) 10 points Sodium vapor lamps, used for public lighting, emit yellow light of wavelength 580 nm. How much energy is emitted by an excited sodium atom when it generates a photon? Correct answer: 3 . 42724 × 10 - 19 J. Explanation: λ = 580 nm = 5 . 8 × 10 - 7 m c = ν λ, so E = h ν = h c λ = 6 . 626 × 10 - 34 J · s 5 . 8 × 10 - 7 m × (3 × 10 8 m / s) = 3 . 42724 × 10 - 19 J 019 (part 2 of 3) 10 points How much energy is emitted by 50 . 2 mg of sodium atoms emitting light at this wave-
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: length? Correct answer: 450 . 661 J. Explanation: mass = 50 . 2 mg = 0 . 0502 g E = . 0502 g Na 22 . 99 g / mol Na × (6 . 022 × 10 23 atoms / mol) × (3 . 42724 × 10-19 J / atom) = 450 . 661 J 020 (part 3 of 3) 10 points How much energy is emitted by 1 mol of sodium ions emitting light at this wave-length? Correct answer: 206 . 388 kJ. Explanation: n = 1 mol E = (1 mol)(6 . 022 × 10 23 atoms / mol) × (3 . 42724 × 10-19 J / atom) = 206388 J = 206 . 388 kJ 021 (part 1 of 1) 10 points Which of the following statements is true re-garding electromagnetic radiation? 1. Electromagnetic radiation with a wave-length of 600 nm has a frequency that is lower than that with a wavelength of 400 nm. cor-rect 2. The frequency of electromagnetic radia-tion determines how fast it travels....
View Full Document

This note was uploaded on 01/23/2011 for the course CH 301 taught by Professor Fakhreddine/lyon during the Spring '07 term at University of Texas at Austin.

Ask a homework question - tutors are online