Department of Chemistry, Geosciences and Environmental Sciences

 

                                                                     Exam 4-A-Key

                       

Chemisty 1084:  Section 010 & 030                                                                       Spring 2006

 

Name:________________________________________________________

 

Read all directions and questions carefully!!  This exam consists of two parts.  The first part consists of 10 multiple choice questions worth four points each for a total of 40 points.  The second part consists of five numerical problems worth either 10 or 15 points per question for a total of 60 points.  Show all your work necessary for the numerical problems as partial credit will be given for those problems.

 

Possibly Useful Constants and Equations

 

     Radioactive decay rates: 

     E = mc2                                                                        1 amu = 1.6605 × 10-27 kg

     c = 2.998 × 108 m/s

 

 

Score

 

                                    Part 1 (40 points):_____________________

 

 

                                    Part 2 (60 points):_____________________

 

 

                                    Total (100 points):_____________________

 

 

Don’t forget to put your name on this test!

 

Good Luck!!

Part 1

 

Multiple Choice

 

Please indicate the answer to each question by putting your choice in the space provided.  There is only one correct answer for each question.  There will be 10 multiple choice questions worth 4 points each.

 

1.  Which one of the following processes results in an increase in the atomic number?

       (a)  gamma emission                                                   (c)  beta emission

       (b)  positron emission                                                 (d)  alpha emission

                                                            (e)  corrosion

 

Answer:  C

 

2.  The smallest number of stable nuclei have an _________ number of protons and an _________ number of protons.

       (a)  odd, odd                                                               (c)  odd, even

       (b)  even, even                                                            (d)  even, odd

 

Answer:  A

 

3.  What type of reaction is known as a thermonuclear reaction?

       (a)  fission                                                                                                            (c)  transmutation

       (b)  fusion                                                                   (d)  beta emission

                                                            (e)  neutron emission

 

Answer:  B

 

4.  Which type of radiation penetrates deepest into living tissue?

       (a)  alpha radiation                                                     (c)  gamma radiation

       (b)  beta radiation

 

Answer:  C

 

5.  Which functional group can be found in the organic molecule below:

       (a)  alcohol                                                                 (d)  ketone

       (b)  ether                                                                     (e)  carboxylic acid

       (c)  aldehyde                                                               (f)  ester

 

Answer:  E

 

6.  What is the hybridization of the astericked carbon in the structure shown in the previous question?

       (a)  sp                                           (b)  sp2                  (c)  sp3                              (d)  dsp3

 

Answer:  C

The astericked carbon in the structure above is a singly bonded carbon atom which has sp3 hybridization.

 

7.  A globular protein describes a protein’s ________________________

       (a)  primary structure                                                  (c)  tertiary structure

       (b)  secondary structure

 

Answer:  C

 

8.  A thermal process that causes reactions between an ore and the furnace atmosphere of the furnace is called:

       (a)  calcination                                                           (c)  smelting

       (b)  roasting                                                                (d)  slag

                                                            (e)  refining

 

Answer:  B

 

9.  A substance with all of its electrons paired up will be:

       (a)  slightly attracted to a magnet.

       (b)  slightly repelled by a magnet.

       (c)  strongly attracted to a magnet.

       (d)  strongly repelled by a magnet.

       (e)  a permanent magnet.

 

Answer:  B

 

10.  The coordination complex, [Co(NH3)4Cl2]Cl produces how many ions when dissolved in water?

       (a)  4                                                                           (c)  2

       (b)  3                                                                           (d)  1

                                                            (e)  0

 

Answer:  C

 

Part 2

 

Numerical Problems

 

Solve the following problems, keeping track of significant figures where applicable.  Please show all the work necessary to obtain your answer in order to receive partial credit for possibly wrong answers.  Generally, full credit will not be given for the correct answer without any of the work performed to obtain the answer being shown on the paper.  Each question is worth either 10 or 15 points.

 

 

11.  (10 points)   Fill in the missing isotope in each of the following nuclear reactions:

The mass number and atomic number of the missing isotope is determined by making sure that the sum of the mass numbers and atomic numbers on both sides of the arrow are equal.

 

(a) 

 

The missing isotope is .

 

(b) 

 

The missing isotope is .  Don’t forget to count the coefficient “2” in front of the product neutron.

 

(c) 

The missing isotope is . 

 

 

(d) 

The missing isotope is . 


12.  (15 points)  The most abundant natural isotope of copper is 63Cu.  It has an atomic mass of 62.93433 amu.  Given the mass of a proton of 1.00728 amu and the mass of a neutron of 1.00866 amu, calculate the binding energy of 63Cu (in units of J) and the binding energy per nucleon (in units of J/nucleon).

 

63Cu has 29 protons and 34 neutrons.  Add up the masses of 29 protons and 34 neutrons and subtract the atomic mass of 63Cu to determine the mass defect:

In order to calculate the mass defect, convert this mass into energy by using E = mc2.  First, convert the mass defect to kilograms:

The binding energy, in units of J, is equal to:

Divide the binding energy by the mass number of 63Cu (63) to obtain the binding energy per nucleon:

13.  (10 points)  Given the following nonmetallic elements discussed in chapter 22:

                       A.  hydrogen                B.  Argon                     C.  Helium                  D.  Xenon

 

                       E.  Fluorine                  F.  Chlorine                  G.  Bromine                H.  Iodine

 

                       I.  Oxygen                     J.  Sulfur                      K.  Nitrogen               L.  Phosphorus

 

                       M.  Silicon                   N.  Graphite                 O.  Diamond

 

Please put the correct letter in front of the item that describes the particular element.  Some choices may have two correct answers.  Not every element is described below.

 

___________ 1.  The most abundant noble gas on the Earth.      Argon (B)

 

 

___________ 2.  Obtained by the fractional distillation of liquid air.  Nitrogen (K) and Oxygen (I)

 

 

___________ 3.  The most stable elemental form of this element consists of molecules containing a ring

                                     of  8 atoms.  Sulfur (J)

 

___________ 4.  An electrical insulator but an excellent conductor of heat.  Diamond (O)

 

 

___________ 5.  This element has the lowest boiling point of all the elements.  Helium (C)

 

 

___________ 6.  Isotopes of this element are given separate names.  Hydrogen (A)

 

 

___________ 7.  The most commercially important halogen.  Chlorine (F)

 

 

___________ 8.  This element is purified by a process called “zone refining”  Silicon (M)

 

 

___________ 9.  The most electronegative element in the periodic table.  Fluorine (E)

 

14.  (10 points)  Answer the following questions about the smelting of iron in a blast furnace.  Iron ore, consisting of Fe2O3, Fe3O4, and silicates; limestone, and coke is poured into the top of the blast furnace.  Hot air is pumped into the bottom of the blast furnace.

 

(a)  What is coke and what happens to it as it falls down the blast furnace? 

 

Coke is a form of carbon.  As it falls down the furnace, it reacts with oxygen to produce carbon monoxide (CO), carbon dioxide (CO2), and heat.

 

(b)  What is the function of the limestone?  What happens to it as it falls down the blast furnace?

 

The limestone consists of calcium carbonate, CaCO3.  As it falls down the furnace, it decomposes into calcium oxide, CaO.  The calcium oxide reacts with silicate impurities in the iron ore to form slag:  CaSiO3.  The function of the limestone is to remove the silicate impurities in the iron ore.

 

 

(c)  What is the primary reducing agent of the iron oxides?

 

Carbon monoxide, CO.

 

 

 

15.  Either give the official name for the given structures, or write the structure for the given names for the hydrocarbons below:

The IUPAC name for the structures is written in italics after the structure.  If a name is not italicized, you needed to write a structure given the name.  The structures are written after this name.

 

(a)                       3-ethylhexane

 

 

 

 

 

 

(b)  3-ethylpentane

 

 

 

 

 

(c)  2,2,4-trimethylhexane

 

 

 

 

(d)                     4-ethyl-2,6-dimethyloctane

 

 

 

 

 

 

 

(e)  cis-2-butene