Ex-1-1413-F12

# P 4 o 10 284 h 2 o 18 co 2 44 co 28 version a chem

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P 4 O 10 - 284. H 2 O - 18. CO 2 - 44. CO - 28.

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Version A CHEM 1413.001 - Exam 1 – Sept. 26, 2012 - Part 2 Name______________________________ FOUR (4) PROBLEMS (You MUST show your work to receive credit) (10) 2. A compound has the following percent composition (by mass): 45.0% carbon(C) 7.50% hydrogen(H) and 47.5% fluorine (F).. Calculate the empirical formula of this compound.
Version A (10) 3. Iridium-192 is a radioisotope used in medicine in the treatment of Breast Cancer. The rate constant for the decay is 9.5x10 -3 hr -1 . If a patient is injected with a sample containing 55 mg of 192 Ir, how many days will it take for the amount of 192 Ir to decrease to 5. mg? (10) 4. When 250 g of a compound containing Phosphorus(P), hydrogen(H) and other elements is burned completely in O 2 , 216. g of P 4 O 10 and 83. g of H 2 O are produced. Calculate the percent (by mass) of P and H in this compound.

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Version A (10) 5. A hypothetical metal carbony has the formula, M x (CO) y . The Molar Mass of the metal is 160 g/mol. When a sample of this compound is burned in oxygen, 86.4 grams of the metal oxide, M 2 O 3 (M=288) and 92.4 grams of CO 2 are formed. Determine the empirical formula of the compound; i.e. determine x and y in M x (CO) y .
CHEM 1413.001 - Exam 1 – Sept. 26, 2012 - Part 2: Version B Constants and Conversion Factors Avogadro's Number: N A = 6.02x10 23 mol -1 Conversion Factors: Molar Masses: C - 12. H - 1. F - 19. P - 31. P 4 O 10 - 284. H 2 O - 18. CO 2 - 44. CO - 28.

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Version B CHEM 1413.001 - Exam 1 – Sept. 26, 2012 - Part 2 Name______________________________ FOUR (4) PROBLEMS (You MUST show your work to receive credit) (10) 2. A compound has the following percent composition (by mass): 23.7% carbon(C) 1.32% hydrogen(H) and 75.0% fluorine (F)..
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