Department of Chemistry, Geosciences and Environmental Sciences

Exam 4-A-Key

Chemisty 1084: Section 010 & 030 Spring 2008

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

Speed of light in a vacuum: c = 2.998 × 10⁸ m/s

E = mc²1 amu = 1.661 × 10^-27 kg

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. Copper-65 decays to zinc-65 by which mode of nuclear decay?

(a) alpha decay (c) positron emission

(b) beta emission (d) gamma decay

(e) spontaneous fission

Answer: B

2. The least number of stable isotopes have an _____________ number of neutrons and an ___________ number of protons.

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

(b) odd, odd (d) equal, equal

(e) even, even

Answer: B

3. The type of nuclear radiation that caused the most ionizations is:

(a) alpha radiation (c) gamma radiation

(b) beta radiation (d) all types of radiation cause equal amounts of ionization.

Answer: A

4. What type of hybridization is observed at a doubly bonded carbon atom?

(a) sp (c) sp²

(b) sp³ (d) dsp³

(e) d²sp³

Answer: C

5. Two molecules that are mirror images but are not superimposable on each other are called:

(a) allotropes (c) structural isomers

(b) optical isomers (d) linkage isomers

(e) geometric isomers.

Answer: B

6. Which element that has the lowest boiling point of any known substance?

(a) hydrogen (c) neon

(b) helium (d) oxygen

(e) nitrogen

Answer: B

7. Heating a metal ore in a furnace and reducing it so that it forms two separate liquid layers is called:

(a) calcination (c) roasting

(b) smelting (d) slag

(e) refining

Answer: B

8. How many ions does the coordination complex [Co(NH₃)₅Cl]Cl₂ form upon dissolving in water?

(a) 0 (c) 2

(b) 1 (d) 3

(e) 4

Answer: D

9. The sequence of amino acids in a protein chain is called the protein’s _______________ structure.

(a) primary (c) tertiary

(b) secondary (d) complete

Answer: A

10. The condensation reaction of an alcohol with a carboxylic acid produces which functional group?

(a) ester (c) aldehyde

(b) ketone (d) amide

(e) alcohol

Answer: A

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) Identify the functional groups in each one of these molecules. (Choices include: alcohol, ether, amine, aldehyde, ketone, carboxylic acid, ester, amide)

12. (15 points) ⁹⁰Zr has an atomic mass of 89.904702 amu.

(a) (8) Given the mass of a proton of 1.00728 amu and the mass of a neutron of 1.00866 amu, calculate the mass defect (in amu) of ⁹⁰Zr.

Zirconium-90 has 40 protons and 50 neutrons. Calculating the mass defect:

The mass defect is 0.8195 amu.

(b) (7) Using the mass defect, calculate the binding energy and the binding energy per nucleon of ⁹⁰Zr.

Convert the mass defect into kilograms:

Calculate the binding energy using E = mc²:

Calculate the binding energy per nucleon (There are 90 nucleons):

13. (10 points) Complete the following nuclear reactions:

(5 points extra credit) Which one of these reactions represents a fission reaction?

Equation (c)

14. (10 points) Carbon from a cypress beam obtained from an ancient Egyptian tomb was found in a cave and dated by its ¹⁴C activity. The ¹⁴C activity was measured at 9.24 disintegrations per minute per gram of material. Given the ¹⁴C activity of living material of 15.3 disintegrations per minute per gram and the half-life of ¹⁴C equal to 5730 y, estimate the age of the cypress beam.

Equation needed:

From the data given in the problem:A = 9.24; A₀ = 15.3,

Using the equation above:
15. (15 points) Given the official IUPAC name for the following structures or write the structures for the following official IUPAC names:

2,5-dimethylheptane

b) 3,3-diethyl-2-methylhexane

2,3-dimethylbutane

d) cyclohexane

trans-2-butene

(5 points extra credit) Which of the following structures is a structural isomer of hexane?

Structure c
For 10 points extra credit:

Define 2 of the following 3 terms. Please remember to choose only 2 of the choices, if you answer all 3 with no indication of which 2 you want graded, only the first two definitions will be graded. Each complete definition is worth 5 points. No partial credit will be given.

Linkage isomers:

Roasting:

Nuclear transmutation: