Chem 209_PS4

Chem 209_PS4 - 2 and.0910g H 2 O In a second experiment...

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Chem 209- Week 4 W 7-8:55 Jaime Ambrosio and Cheng Cheng 1. a) An excited sodium atom emit lights as it undergoes a transition from one energy level that is 3.61 x 10 -19 J lower in energy. Determine the wavelength in nm and the color of the light you would expect to see in the flame. b) WVBR broadcasts at 93.5 MHz. What is the wavelength and energy of this radio signal? Some questions from previous prelims (point values (out of 175) are included for your benefit): 2. (15 points) (a) Using Bohr theory, compute the distance (in Å) of an elecron in a Ne 9+ atom in n=4. (b) What is the uncertainty in the velocity of the electron if we know the position to 1% of this value? 3. a) (15 points) The Paschen series of lines are defined as those arising from one electron atoms with n f = 3. An unknown ion was found to have its least energetic line at a wavelength of 117.3 nm. What is this ion?
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(extra practice) 4. Burning a .137g sample of quinine in excess oxygen gives .372g CO
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Unformatted text preview: 2 and .0910g H 2 O. In a second experiment, a .183g sample is found to contain .0158g of N. Determine the chemical formula of quinine given that its molar mass is between 300 and 350g/mol. (more from previous exams) 5. A fuel “Aerozine-50” is a 50:50 blend (by mass) of N 2 H 4 and (CH 3 ) 2 N 2 H 2 . N 2 O 4 is used as an oxidant to initiate the combustion process. a) (5 points) Balance the chemical equations for the combustion of Aerozine 50: N 2 H 4 + N 2 O 4 N 2 + H 2 O (CH 3 ) 2 N 2 H 2 + N 2 O 4 N 2 + H 2 O + CO 2 b) (10 points) *Consider only the combustion of hydrazine* If 500kg of both reagents are mixed, how many kg of N 2 are produced? 6. (25 points) The active ingredient in pepto bismal contains at least 3 (maybe more) elements: C, H, and Bi. Combustion of .22105g of the active ingredient produced .1422g of Bi 2 O 3 , .188g of CO 2 and .0275g of water (and nothing else). What is the empirical formula of the compound?...
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Chem 209_PS4 - 2 and.0910g H 2 O In a second experiment...

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