Final Exam - Chemistry 201X Sample Final 1(1 Using a new catalyst a chemist has made an unusual organic halide in nearly 100 yield that analyzes as

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Chemistry 201X: Sample Final 1 (1) Using a new catalyst, a chemist has made an unusual organic halide in nearly 100% yield that analyzes as 24.79% carbon, 2.09% hydrogen and 73.12% chlorine, by mass. (a) Determine the empirical formula of this compound. (b) Using the mass spectrum of this compound and the information about the element’s isotopes, determine the molecular formula . ( 1 H: 100%; 12 C: 100%; 35 Cl: 75%; 37 Cl: 25%) Mass Number (amu) 0 1 02 03 04 05 06 07 08 09 01 0 0 Relative Intensity 0.0 0.1 0.2 0.3 0.4 0.5 0.6 (c) Write a Lewis structure of this molecule, showing its correct molecular structure. (The mass spectrum should help you.) (d) The boiling point of this compound is 37 ° C. The boiling point of a similar compound but with F atoms rather than Cl atoms (same number of C and H atoms) is 84 ° C. What is the main reason for the higher boiling point of the chloride compound?
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Chemistry 201X: Sample Final 2 (2) At 500.0 K, ammonium nitrate, NH 4 NO 3 (s) (FW = 80.04 g/mol), decomposes into nitrous oxide, N 2 O(g) and water vapor. (a) Write the balanced chemical equation for this reaction using integer coefficients. (b) If this reaction at 500.0 K is carried out with 10.00 g ammonium nitrate in a 12.00 L closed cylinder, what is the total pressure (in atm) once all of the solid has decomposed? Assume ideal gas conditions. (c) On the graph below, the distribution of molecular speeds for N 2 O(g) at 500.0 K is shown. Draw the graph for water vapor at 500.0 K. Speed Relative Probability (d) At what temperature (in K), do you expect the water vapor to condense if the pressure of the gas mixture is kept constant during cooling? H vap (H 2 O) = 40.7 kJ/mol. (HINT: what is the partial pressure of water vapor in the gas mixture?)
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Chemistry 201X: Sample Final 3 (3) The mineral cuprite adopts the cubic structure with the unit cell shown below. The side of the cubic unit cell is 461.9 pm. Open circles are oxygen atoms; filled circles are copper atoms. (a) (4 pts) What is the empirical formula of cuprite? (b) What is the density (in g/cm 3 ) of cuprite? (c) Identify the oxidation state of the Cu ion in this compound and write down the electronic configuration of this ion. Underline the valence electrons in your electronic configuration. (d) Cuprite, an insulator, can be examined in a scanning tunneling microscope (STM) because under the extremely low pressures, some Cu atoms are released from the solid. In 2-3 sentences, describe how the STM works.
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Chemistry 201X: Sample Final 4 (4) When the brown gas, NO 2 (g), is bubbled into water, nitric acid, HNO 3 (aq), and nitric oxide, NO(g), form.
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This test prep was uploaded on 03/27/2008 for the course CHEM 201 taught by Professor Miller during the Fall '07 term at Iowa State.

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Final Exam - Chemistry 201X Sample Final 1(1 Using a new catalyst a chemist has made an unusual organic halide in nearly 100 yield that analyzes as

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