1411 Practice Exam 2

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					     Chemistry 1411 Practice Exam 2, Chapters 5-8 Chang

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Some constants and equations:

1 atm = 760 torr           PA = XAPT              r1/r2 = (M2/M1)1/2
E = q + w                 Heat = CT             Heat = m C T
             –34  .
h = 6.63 X 10    Js        c = 3.00 X 108 m/s     RH = 2.18 X 10–18 J
E = (2.18 X 10–18 J)(1/ni2 – 1/nf2)              E = h = hc/
R = 0.08206 L.atm/mol.K = 8.314 J/ mol.K

A periodic table is also attached to the end of the exam.
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1.   A balloon originally had a volume of 5.39 L at 44C and a pressure of
     755 torr. To what temperature must the balloon be cooled to reduce its
     volume to 4.00 L at a pressure of 620 torr?
     a) 18C             b) 0C          c) -50C            d) -80C




2.   A gas in a 500 milliliter container is found to have a pressure of
     758 torr at 22.0C. How many moles of gas are in the flask?
     a) 2.47 X 10-2      b) 2.06 X 10-2 c) 9.42              d) 12.4




3.   What is the density of O2 gas in grams per liter at STP?
     a) 1.43             b) 1.97        c) 2.86             d) 3.19




4.   The ratio of the rates of effusion of CO2 and gas X is 1.0224.
     What is gas X?
     a) O2             b) F2             c) SO2             d) NO2
5.    A sample of aluminum metal was reacted with hydrochloric acid,
      producing AlCl3(aq) and H2 gas. If 5.00 g of aluminum was reacted,
      how many liters of H2 gas would be produced at STP?
      a) 6.23        b) 5.19             c) 4.58             d) 9.74




6.    A gas mixture consists of 1.00 g of H2 and 1.00 g of O2. If the total
      pressure is 1.00 atm, what is the partial pressure of H2?
      a) 0.249 atm   b) 0.500 atm         c) 0.733 atm        d) 0.941 atm




7.    The first law of   thermodynamics states
      a) All reactions   are exothermic.
      b) All reactions   produce work.
      c) The work done   by a reaction equals the amount of heat it produces.
      d) Energy is not   created or destroyed in any reaction.


8.    When a   reaction absorbs   heat   under constant pressure conditions,
      a) the   heat = H and H   will   be negative.
      b) the   heat = H and H   will   be positive.
      c) the   heat = E and E   will   be positive.
      d) the   heat = E and E   will   be negative.


9.    H° for the reaction 2N2(g) + 6H2(g)  4NH3(g) is –184.8 kJ.
      What is H° for the reaction 2NH3(g)  N2(g) + 3H2(g) ?
      a) +184.8 kJ   b) +92.4 kJ          c) –92.4 kJ         d) +369.6 kJ




10.   What is the E of a system that releases 124.4 J of heat to the
      surroundings and does 18.2 J of work to the surroundings?
      a) 106.2 J     b) –106.2 J          c) 142.6 J          d) –142.6 J
11.   A 2.85 g sample of a food substance   was burned in a calorimeter that
      had a heat capacity of 9.84 kJ/°C.    The temperature of the calorimeter
      increased from 22.51°C to 35.66°C.    Calculate the amount of heat
      released per gram of the substance.
      a) 56.17       b) 49.98               c) 45.40              d) 28.44




12.   The specific heat of liquid mercury is 0.14 J/g°C. How many joules of
      heat would be required to raise the temperature of 3.75 g of mercury
      from 25°C to 65°C?
      a) 19          b) 25                c) 16               d) 21




13.   A sample of aluminum metal at 75.0°C was placed in 100 mL of water at
      24.0°C in a coffee cup calorimeter. The final temperature was 28.0°C.
      What was the mass of the aluminum? The specific heat of aluminum is
      0.900 J/g°C and the specific heat of water is 4.184 J/g°C.
      a) 12.5 g      b) 28.0 g            c) 39.6 g           d) 351 g




14.   Use reactions 1 and 2 to determine the value of H° (in kJ) for
      reaction 3.

      (1)   N2(g) + 2O2(g)  2NO2(g)             H°   =   +67.6 kJ
      (2)   NO(g) + 1/2 O2 (g)  NO2(g)          H°   =   –56.6 kJ

      (3)   N2(g) + O2(g)      2 NO(g)          H°   =   ?
15.   The combustion of ammonia with oxygen occurs by the reaction

      4 NH3(g) + 7 O2(g)      4 NO2(g) + 6 H2O(g)       H° = –1132 kJ

      Calculate the amount of heat released when 2.00 gram of NH3 is
      combusted. (Hint: How many moles of NH3 is this?)

      a) 33.2 kJ     b) 87.0 kJ             c) 11.4 kJ             d) 16.6 kJ




16.   From the following information,

      Substance      Hf° (kJ/mole)
         MgO(s)         -601.8
         HCl(g)         -92.3
         MgCl2(s)       -641.6
         H2O(l)         –285.8

      calculate H° in kJ for the following reaction:

      MgO(s) + 2 HCl(g)       MgCl2(s) + H2O(l)

      a) +122 kJ           b) –122 kJ              c) +141 kJ      d) –141 kJ




17.   What is the wavelength of light that has a frequency of 1.20 X 1015 s–1 ?
      a) 2.50 X 10–7 m    b) 1.20 X 108 m      c) 25.0 cm     d) 3.60 X 10–4 m




18.   Which type of electromagnetic radiation has the highest energy?
      a) UV               b) radio             c) visible     d) gamma


19.   What is the wavelength of a photon with an energy of 5.25 X 10–19 J?
      a) 3.79 X 10–7 m         b) 2.64 X 106 m
                  23
      c) 2.38 X 10 m           d) 4.21 X 10–24 m
20.    Calculate the energy change associated with an electron transition from
       n=1 to n=6 in a hydrogen atom.
       a) 2.12 X 10–18 J        b) 5.52 X 10–18 J
                   –18
       c) 1.89 X 10    J        d) 4.60 X 10–19 J




21.    The values of the principal quantum number (n) and the secondary
       quantum number (l) of an electron in a 3p orbital are
       a) 2, 3              b) 3, 2        c) 3, 1             d) 2, 2



22.    Which set of quantum numbers cannot be correct?
       a) n = 1, l = 0, ml = 0             b) n = 3, l = 2,     ml = –2
       c) n = 3, l = 2, ml = –2            d) n = 5, l = 5,     ml = 3



23.    The term degenerate orbitals indicates that the orbitals

       a)   contain the maximum number of electrons
       b)   have different principal quantum numbers
       c)   have the same energy
       d)   have different energies


24.    Which diagram represents a violation of the Pauli exclusion principle?
            
            

                   
                   




                                              
                                              

                                                       
                                                       
                          

                              




                                                            



                                                                      
      a)                                 b)
             1s     2s        2p               1s      2s       2p
             




                          

                              

                                   




                                                            
                   
                   




                                              
                                              

                                                       
                                                       




                                                                      



      c)                                 d)
             1s     2s        2p               1s      2s       2p




25.    Write the electron configuration of nickel. Show
       the complete configuration, starting with the 1s orbital.


       Ni     _____________________________________________________
26.   Draw the orbital (box) diagram electron configuration for the element
      fluorine. Label the boxes. You may use the noble gas label for the
      inner electrons if you desire.



      F    _____________________________________________________




27.   Rank the following elements below in order of increasing atomic radius
      (smallest to largest): Mg, Na, P, Si, Ar

      a) Mg, Na, P, Si, Ar     b) Ar, P, Si, Mg, Na
      c) Si, P, Ar, Na, Mg     d) Na, Mg, Si, P, Ar


28.   Which one of the following atoms has the largest effective nuclear
      charge, Zeff?
      a) C           b) N                 c) O                d) F


29.   Which of the following elements has the highest ionization energy?
      a) Na          b) Li                c) Cl               d) Ca


30.   When a metal and a nonmetal react, which one tends to lose electrons?
      a) the metal             b) the nonmetal           c) either


31.   Which one of the following ions has the largest radius?
      a) Na+         b) Al3+              c) P3–              d)F–


32.   Which will form an acidic solution when dissolved in water?
      a) Li2O        b) Na2O              c) CO2              d) MgO
                                       Answers


1.    D                      11.   C
2.    B                      12.   D
3.    A                      13.   C
4.    D                      14.   +180.8 kJ
5.    A                      15.   A
6.    D                      16.   D
7.    D                      17.   A
8.    B                      18.   D
9.    B                      19.   A
10.   D                      20.   A




21.   C
22.   D
23.   C
24.   A
25.   1s2 2s2 2p6 3s2 3p6 4s2 3d8
      Can you give the configuration for the Ni2+ ion?

26.        0      0    –1     0    1     ml
           ↑↓     ↑↓    ↑↓   ↑↓    ↑
           1s    2s          2p          type of orbital

          Can you give the four quantum numbers for each electron?


27.   B
28.   D
29.   C
30.   A
31.   C
32.   C

				
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