Question

the date is 4/09/19

POST-LABORATORY QUESTIONS (For full credit show your calculations). us T able enced color of light and the coresponding wavelength (om) associated with each cation Barium, Ba2 Copper, Cu2 Sodium, Na Calcium, Ca2 Potassium, K Strontium, Sr2 2. Calculate the energy associated with the light emitted by each of the K', Ca*2 and Li. Ca 2 Ba*2 s Flame Tests & Electron Configuration FLAME TESTS & ELECTRON CONFIGURATION INTRODUCTION AND BACKGROUND The chemistry of an element strongly depends on the more stable energy levels, ene arrangement of the electrons. When electrons f energy, they can attain higher energy levels. In order to return to the lower. electrons release energy. If the energy released is the same amount as the y that makes up visible light, the element produces a color When heated, many of the elements in Groups 1A and 2A produce colorful flames. Fach ale produces a characteristic color. When the light from one of these flames passes through a glas or crystal, a series of color lines appears. The spaces between lines appear dark. Such ase known as a spectrum, is used to identify elements in water, food, the sun, stars, and on other The color of the light corresponds to the energy released when an excited electron drops to a lower energy state releasing energy in the visible portion of the electromagnetic spectrum. Blue light thus corresponds to the highest or greatest amount of energy released versus the red light which is lower in energy The energy of the light emitted can be estimated using Planck's equation for energy, E h hc/2, where h is Planck's constant (6.63 x 10* J s), c is the speed of light in a vacuum (2.998 x 10 m/s), v is the frequency in s, and is the wavelength in meters. For example, the energy, E, of the light emitted by arsenic, As, can be estimated as follows, using Table 1, equations 1 and 2 below: Convert wavelength to meters (equation 1): 2 419 nm x 1 x 10 nm 4.19x 10-7m Calculate energy (equation 2): he (6.63x10-MJ $)(2.998 x 10° m/s)4.19x 10-19 24.19x 10 m Table 1. Cations and Colors they Produce in an lonizing Flame Name Color Wavelength, nm 419 478 516 585 ht Green Light green Pale violet Blue l) (halide) Blue-green (bluish green) 481 451 671 Crimson Il) Yellowish green ellowish green Intense yellow Pale bluish green Pale green Pale violet Pale green 525 536 568 458 520 408 563 473 640 Sr ala ls proposed the "nrtet ndn Flame Tests &Electron Configuration Elements omic Number (2), Radius, First lonization Energy & Valence Electrons for Selected # Valence e- Radius (pm) 37 Symbol Z 1" lon Energy (kumol) First period Hydrogen H 1312 2373 Li 8 N 520 899 801 1086 1400 1314 152 Berylium Be Boron Carbon Nitrogen Oxygen 60 FluorineNe 1680 2080 64 10 Na 11 186 Mg 13 117 495.9 738.1 577.9 786.3 1012 999.5 1251 1521 14 143 110 16 104 Aluminum A 15 Sulfur Argon Ar18 94 Potassium K Calcium Ca 231 197 418.7 589.5 20 EXPERIMENTAL PROCEDURE Light the Bunsen burner at your station and adjust the flame of the Bunsen burner until it is nearly colorless. Remove, in turn, each cork from its tube and heat only the loop end in the flame. You are looking for a short lived burst or flickering of color in the flame, consult Table 5.1 when testing solutions containing known cations. You will have to test & retest each solution several times by dipping the wire loop into the solution and then reheating it in the Bunsen burner flame. Test the color of each of the labeled, known solutions and unknowns several times and record your observations below. Your task is to correcthy O o Date: 4/6/a Flame Tests Description of Flame Color Solution Cation BaCl CaCla CuCl Bat2 ieen heo Cu*2 uven KCI NaCl SrClz Na· bricht yollir liang |いさ!Yeo-owner Unknown 1 Unknown 2 /lilac Unknown Nt Gnp Unknown 3 Write the electron configuration for each of the known and unknown cations tested Li

Answer 1

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