Chem 1102Exam 2BMarch 8, 200650 points

Name______KEY______Section______

I.(28) Multiple Choice (14 questions @ 2 points). ). Circle correct answer on exam and mark correct answer on Scantron. Put your name and section number on Scantron.

1.The correct equation for radioactive decay via alpha particle emission is

A. 21H + 21H  32He + 10n

B. 10n + 23592U  14256Ba + 9136Kr + 3 10n

**C.17979Au  17577Ir + 42He

D.10n + 23892U  23992U

2.The three most common greenhouse gases are

1.H2O

2.CH4

3.CO2

4.Hg

5.SO2

**A.1, 2, 3

B.3, 4, 5

C.2, 3, 5

D.1, 3, 4

3.The correct equation for a fission reaction is

A. 21H + 21H  32He + 10n

**B. 10n + 23592U  14256Ba + 9136Kr + 3 10n

C.17979Au  17577Ir + 42He

D.10n + 23892U  23992U

4. The correct formula for an ionic compound containing lithium and oxygen is

A.LiO

B.LiO2

C.Li3O

**D.Li2O

5.What statements are true about Figure 16.10

1Approximately 25% of the greenhouse gas CO2 produced in fossil fuel combustion and cement production is deposited in the ocean.

2.Forests and land use are net producers of the greenhouse gas CO2.

3.Approximately 50% of the greenhouse gas CO2 produced in fossil fuel combustion and cement production persists in the atmosphere.

4.Approximately 50% of the greenhouse gas CO2 produced in fossil fuel combustion and cement production is deposited in the ocean.

A.1

B.2, 4

**C.1, 3

D.2, 3, 4

6.The pH of a 1.38E-5 M solution of nitric acid, HNO3 is

A.10

B.9.13

C.7.35

**D.4.86

7.Left untreated, soils

**A.become more acidic

B.become more basic

C.maintain a pH = 7

D.produce lye

8. Oceans are becoming more acidic mainly because of this chemical reaction

**A.CO2 + H2O  H2CO3

B.CH4 + 2O2  2H2O + CO2

C.SO3 + H2O  H2SO4

D.H2O  H+ + OH-

9.In the oceans, coral, phytoplankton and shellfish are threatened because H+ competes with ____ for the carbonate ion.

A.Cl-

B.Na+

C.HCO3-

**D.Ca2+

10.C-14 has a half-life = 5730 years. If a piece of petrified wood has 12.5% of its original radioactivity, how old is the wood?

A.5730

B.11,460

**C.17,190

D.22,920

11.The normal pH of blood and pristine oceans is

**A.slightly basic

B.slightly acidic

C.very basic

D.very acidic

12. All of the following observations over the past one hundred years are consistent with global warming except

**A.mosquito-borne diseases have reached lower altitudes

B.average global precipitation has increased

C.sea level has risen

D.greenhouse gases have increased in the atmosphere

13.The terms Tokamak, solar energy, ITER and hydrogen bomb are associated with

A.global warming

**B.fusion reaction

C.gamma emission

D.fission reaction

14.U-235 and U-238 can be separated because of differences in their

A.radioactivity decay pathways

B.number of electrons

C.radioactive half-lives

**D.masses

II.(10) Short Answers

1.Tritium has __2__ neutrons and __1__ protons.

2.The last nuclear power plant in the US was built in ____1979______.

3.T or FGatorade replaces water and ions lost through exercise.

4.T or FThe greenhouse gas CO2 is mainly produced via human activities

5.Nonmetals tend to [lose, gain, react with] electrons and form [cations, anions, beta particles]

.

III.(12) Problems

1.(4) Define the role of greenhouse gases in global warming. Include the following in your answer: solar radiation, absorption of thermal radiation, fossil fuels, enhanced greenhouse effect, increase in average global temperature since 1900.

Radiation (UV) from the sun falls on the earth’s surface and warms its atmosphere and surface. Some of the solar radiation reflects off the latter back into the atm. Greenhouse gases such as H2O, CO2, CH4, N2O in the atm absorb this reflected radiation at specific wavelengths and convert it to thermal energy which warms the atm; this is called the greenhouse effect. Solar radiation is necessary to sustain life on earth. But since 1900, the amount of greenhouse gases has increased dramatically due to increases in fossil fuel combustion which producesCO2. As a result more reflected solar radiation has been absorbed and the earth’s atm has warmed up even more (global warming). This is called the enhanced greenhouse effect. We see evidence of global warming in increases in the atm’s temperature, levels of precipitation, melting of polar ice caps, rise in sea level, changes in growing seasons, etc.

2.(2)Write the nuclear reaction for 6127Co decay via beta emission.

6127Co  6128Ni + 0-1e

3.(4)Compare a chemical, fission and fusion reaction by filling in the blanks.

Chemical / Fission / Fusion
Starting material / Coal / U-235 / Isotopes of hydrogen
Required temperature / 700K / 1000K / 100 million K
Energy produced / 1E+2 J / 1E+XX J where XX = 12 / 1E+14 J
Radioactive Waste / none / substantial / minimal

4.(2)Write a balanced chemical reaction for Milk of Magnesia (Mg(OH)2) neutralizing stomach acid (HCl).

Mg(OH)2 + 2HCl  2H2O + MgCl2

EXTRA CREDIT (4)

1.The Duluth News-Tribune article presents mercury levels in

A.2007 federal standard

B.waste water leaving the water treatment plant in Duluth

C.rainwater

D.treated water entering the water treatment plant in Duluth

Arrange the letters, A, B, C and D in order of increasing ppt (lowest to highest)

A < B < C < D

2.The article states that Minnesota has reduced Hg by “70% since 1990 from 8,881 pounds annually to 739”. This % is wrong. Calculate the correct percentage reduction.

[739/8881] 100 = 92%

3.Approximately __80____ pounds of Hg enter the atmosphere each year due to the creation of corpses with dental fillings

1