# Pages CH217 - Home CH217 - Homework

## Homework Assignment 1: General Chemistry Review (due 2/8/2010)

1. Get a General Chemistry text that you may use as a reference for the semester.
2. Complete the attached CH141 and CH142 exams (you may consult each other, but must submit your own work).  Please turn in a hard copy in class.
Ch142 Final 2000.pdf           CH141 Final Exam 2003.pdf

## Homework Assignment 2: Room Energy Audit (due 2/15/2010)

Every student will help prepare a Colby student energy audit of electrical appliances used by the student body.  Start by claiming an appliance by adding your name to the table below.  You may fill in the rest of your row at a later date.

Name

Appliance

Energy Consumption (J/year)

Number on Campus

Total Energy

example

microwave

3.73 * 10^4 kJ/year

1077.1

4.01 * 10^7 kJ

Sarah

Cell chargers

1.45 *10^7 J/year

1764

2.56 *10^7kJ

Andy

Laptop chargers

4.60 E8 J/year

1867

8.59 E8 kJ

Reuben

Televisions

99600kj/female-yr; 24300kj/male-yr

960 female; 790 male

2.88 E8 kJ/yr

Erin

Hair Straighteners

1.96 * 10^7 J/year

966.7

3.45 *10^7 kJ

Rachael

Lamps

9.58 E7 J/yr

1717

1.65 E8 kJ

Amy

Refrigerators

2.7 * 10^8 J/year

600

1.62 * 10^9 kJ

Devon

Speakers

6.93 * 10^7 J/year

1235

8.56 * 10^7 kJ

Mike

Electric Razors

1.79 * 10^3 J/year

706

1.26 * 10^5 kJ

Kimberly

clocks

1.36 x 10^8 J/yr

752

2.4 x 10^8 kJ/yr

Greg

Coffee Maker

1.281 x 10^5 kJ/year

176.4

2.260 x 10^7 kJ/yr

Josie

Microwave

5.3 * 10^5 kJ/year

875

4.6 * 10^8 kJ

Trevor

Gaming Console

Once you have selected the appliance, survey 10 or more rooms to get a statistical sampling of the appliance frequency on campus.  Determine the energy consumed by the appliance over the course of the academic year and compute the total energy consumed by all students using the appliance.  Put your data in the table above and provide the details on your appliance and your calculations below.  This assignment is only submitted on this page.

Post answers to assignment 1 below:  (list name, appliance, and then details)
Steve Jobs, Apple laptop computer

Details on the calculations for computer energy consumption ....

_______________________________________________________________________________________________

Example, Blow Drier

 Brand Voltage (V) Current (A) Power (W) 1 Jilbere 125 10 1250 2 Physique 125 15 1875 3 Revlon 125 15 1875 4 Conair 125 15 1875 5 Perfection Classic 125 15 1875 6 Vidal Sassoon 125 15 1875 7 Conair 125 15 1875 8 Conair 125 15 1875 9 Conair 125 15 1875 10 Conair 125 15 1875 Average 1812.5

Average Energy Consuption a year assuming 10 minutes daily use.

1812.5 J/sec * 60 sec/min * 10 min/day * 365 day/year = 3.97E8 J

Assuming every female (54.8%) on campus and no males use a blow dryer (some guys have hair driers)

3.97E8 J * 1867 * 54.8% = 4.06E11 J = 4.06E8 kJ

Electric Razors

Sample #

Brand

Use (min/week)

Voltage (J/c)

Current (c/sec)

Power (J/sec)

1

Braun

10

12

0.400

4.8

2

Braun

12

12

0.400

4.8

3

No Razor

4

No Razor

5

No Razor

6

Phillips Norelco

7

15

0.420

6.3

7

Phillips Norelco

12

15

0.420

6.3

8

No razor

9

No razor

10

No razor

Average

40% of student body

10.25

5.6

Average Energy Consumption:

5.6 J/sec * 60 sec/min * 10.25 min/week * 52 weeks/year = 1.79 * 10^3 J/year

Assuming only males use electric shavers

1.79 * 10^3 J/razor/year * 1764 students * 0.40 razors/student * 1J/1000kJ = 1.26 * 10^5 kJ/year

Devon McIntyre, iPod/Computer Speakers

Sample #

Brand

Voltage (V)

Current (A)

Power (W)

1

Altec Lansing,
InMotion

100 - 240

0.8

80

2

Logitech

120

0.525

63

3

Bose

120

0.16

19.2

4

Bose

120

0.16

19.2

5

JBL

120

0.183

22

6

JBL

120

0.183

22

7

JBL

120

0.183

22

8

Klipsch

100 - 240

max 1.5

150

9

iSymphony

120

0.9

108

10

JBL

120

0.183

22

Average

52.74

Average energy consumption in a year assuming speakers are used 1 hour per day:

52.74 J/sec *  60 sec/1 min  * 60 min/1 day  *  365 days/1 year  = 6.93 E7 J/year

Colby students total – 1838

% Colby students on campus – 96%

Total Colby students on campus – 1764

Assume 70% of students have speakers – 1764  * .70  =  1235 students with speakers on campus

1235* * *  6.93 E7 J  =  8.56 E10 J  =  8.56 E7 kJ/year

_______________________________________________________________________________________________

Rachael Mack: Lamps

 Brand Voltage (V) Current (A) Power (W) 1 Walmart 120 0.5 60 2 120 0.33 40 3 Your Zone 120 0.33 (40*5 bulbs) 200W 4 120 0.33 40 5 Jansjo 120 0.09 10.8 6 Jansjo 100 0.09 0.09 7 Walmart 120 0.12 14 8 120 0.5 60 9 120 0.33 40 10 Walmart 120 0.12 14 Average 48.78

Assuming there is on average one lamp per person, and each person uses it daily for about 1.5 hours. (Approximately 93% of the total student body lives on campus – 1717 students.)

48.78 J/s * 60 s/min * 90 min/day * 365 day/yr = 9.61 E7 J/yr

9.61 E7 J/yr * 1717 students = 1.65 E8 kJ/yr

_______________________________________________________________________________________________
*Reuben Biel, Television*

 Room No Brand Volt (V) Current (A) Wattage (W) Time (hrs_used/day) Occupants Gender kJ Used per Room per Day kJ Used per Individual per Day 1 Sylvania 120 0.44 53 0.57 3 M 109.0285714 36.34285714 2 Emerson 120 0.5 60 1 2 F 216 108 3 --- 0 0 0 0 2 M 0 0 4 Orion 120 0.92 110 1 2 F 396 198 5 Olevin 120 1 100 1.5 3 M 540 180 6 --- 0 0 0 0 2 F 0 0 7 --- 0 0 0 0 3 M 0 0 8 Emerson 120 0.46 55 1 2 F 198 99 9 Magnavox 120 2 240 0.57 1 M 493.7142857 493.7142857 10 Magnavox 120 0.33 40 5 1 M 720 720 11 RCA 120 0.46 55 1.5 1 F 297 297 12 LG 120 1.25 150 6 1 M 3240 3240 13 Insignia 120 0.58 70 0.5 0.5 F 126 --- 13A LG 120 1.25 150 2 0.5 F 1080 --- 13 Total 0 0 0 0 1 F 0 1206 14 --- 0 0 0 0 1 F 0 0

Assuming that Televisions only draw energy while being used (false assumption so is an underestimate of actual usage):
Average Usage per Female per Day (including those without TVs): 273 kJ/day
Average Usage per Male per Day (including those without TVs): 667 kJ/day
If there are approx. 960 females (54.8%) and 790 males on campus (Total 1750 students), then:
Total Female Usage per Year = 273 kJ/female-day*365 days/yr*960 females = 9.55E7kJ/yr
Total Male Usage per Year = 667 kJ/male-day*365 days/yr*790 males = 1.92E8kJ/yr
Total Energy Usage per Year = 9.55E7kJ/yr + 1.92E8kJ/yr = 2.88E8kJ/yr

| Room | Brand | Voltage (V) | Current (A) | Power (W) |

 1 0 0 0 0 2 0 0 0 0 3 0 0 0 0 4 Timex 120 0.05 6 5 Memorex 15 1 15 6 Sony 120 0.04 5 6 0 0 0 0 6 0 0 0 0 7 Sony 120 0.04 5 8 RCA 22 1 22 8 iPod 15 1.5 22.5 9 0 0 0 0 9 0 0 0 0 9 0 0 0 0 10 0 0 0 0 11 0 0 0 0 12 Sony 120 0.04 5 13 0 0 0 0 14 Sony 120 0.04 5 15 Memorex 120 0.04 5 16 0 0 0 0

Number of students with alarm clocks:

9/21 students in the survey = 43 % x ~1750 students on campus = 752 students

Average power use of alarm clocks: 10.0 W

Total Average power use (including non-owners): 4.3 W

Yearly Average Power Use per student:

4.3 J/sec x 60 sec/min x 60 min/hr x 24 hr/day x 365 day/yr = 1.36 x 10^8 J/yr

Campus Power use:

1.36 x 10^8 J/yr x 1750 students = 2.40 x 10^11 J/yr x 1 kJ/1000 J = 2.40 x 10^8 kJ/yr

Josie Thiele, Microwave Oven

 Brand Voltage (V) Current (A) Power (W) 1 Cuisinart 120 8 1000 2 120 8 1000 3 GE 120 9 1100 4 120 9 1100 5 LG 120 13 1500 6 120 13 1500 7 120 13 1500 8 Sharp 120 9 1100 9 120 9 1100 10 Frigidaire 150 6 900 Average 1180

Assuming that there is one microwave per room (and each room has 2 people in it), and each room uses it for 20 minutes a day.

Yearly Average Power Use per microwave

1180J/s*60s/min*20min/day*365day/yr*1kJ/1000J=5.2*10^5kJ/yr

Annual Campus Power Use

Assuming there is one per room, ~875 rooms

5.2*10^5kJ*875rooms=4.6*10^8kJ/yr

*Erin Schnettler-Hair Straightners

 89.4W Sample Brand Voltage (V) Power (W) 1 Emperor 110V 200W 2 Solia 110V 58W 3 Sedu 110V 72W 4 Solia 110V 58W 5 CHI 110V 35W 6 Sedu 110V 72W 7 Conair 120V 36W 8 Solia 110V 58W 9 Hot Tools 110V 170W 10 Solano 110V 135W Avg.

--Average Energy Consumption per year assuming 10 minutes of daily use
89.4J/sec*(60sec/min)(10min/day)(365days/year)=19578600 J/year

--Avg. Energy Consumption per year assuming that use is limited to all females on campus:
19578600 J * 1,764 students * .548 =3.454*10^10 J (1 kJ/1000 J) = 3.45*10^7 kJ/year

_______________________________________________________________________________________________

Greg Klein: Coffee Makers

 1812.5 Brand Voltage (V) Current (A) Power (W) 1 Mr. Coffee 120 7.5 900 2 120 7.5 900 3 Black and Decker 120 10 1200 4 Cuisinart 120 13.833 1660 5 120 13.833 1660 6 Cuisinart 120 9.166 1100 7 120 9.166 1100 8 Hamilton Beach 120 7.5 900 9 Hamilton Beach 120 12 1140 10 120 12 1140 Average

Assuming about one in ten students has a coffee maker:

0.1 x 1764 students = 176.4 students

Average yearly power consumption, assuming 5 minutes daily use:

1170 J / sec x 60 sec / min * 5 min x 365 = 1.281 x 10^8 J / year

Total power consumption for the campus:

1.281 x 10^8 (J / year x students) x 176.4 students = 2.260 x 10^10 J / year

2.260 x 10^7 kJ / year

Andy Oakes, Laptop Chargers

-->| Sample | Brand | Voltage | Current | Power |

 1 Macbook 16.5V 3.65A 60W 2 Macbook Pro 16.5V 3.65A 60W 3 Dell Latitude 19.5V 3.34A 65W 4 Dell Inspiron 19.5V 3.34A 65W 5 Macbook Pro 16.5V 4.6A 85W 6 HP Compaq 19V 4.74A 90W 7 Macbook Pro 16.5V 3.65A 60W 8 Macbook 16.5V 3.65A 60W 9 Dell Inspiron 19.5V 3.34A 65W 10 Gateway NV 19V 4.74A 90W Average 70W

Average Energy Consuption a year assuming 300 minutes daily use.

70 J/sec * 60 sec/min * 300 min/day * 365 day/year = 4.60E8 J/year

Assuming everyone on campus has a laptop

4.60E8 J * 1867 = 8.59E11 J = 8.59E8 kJ

Sarah Dallas-- Cell Phone Chargers

sample

brand

voltage (V)

current (A)

Power (W)

1

LG

5

1

5

2

BlackBerry

5

0.7

3.5

3

BlackBerry

5

0.7

3.5

4

Samsung

5

0.7

3.5

5

LG

5.1

0.7

3.57

6

LG

5.1

0.7

3.57

7

Motorola

5

0.55

2.75

8

LG

4.8

0.9

4.32

9

LG

5.1

0.7

3.57

10

BlackBerry

5

0.7

3.5

Average

3.678

1764 chargers on campus, because every student has a cell phone

Assume they are used by everyone for 3 hours a day every day of the year

3.678 J/sec * 60 sec/min * 60 min/hr * 3 hr/day * 365 days/yr = 1.45E7 J/yr

Power*#of chargers >> 1.45E7 * 1764 = 2.56E10 J >> 2.56E7 kJ

Trevor Poole - Game Consoles

Sample #

Brand

Use (min/week)

Voltage (V)

Current (A)

Power (W)

1

Xbox 360

120

12

12.1

150

2

None

0

0

0

0

3

None

0

0

0

0

4

Xbox 360

60

12

14.2

175

5

None

6

Wii

90

12

3.7

33

7

None

0

0

0

0

8

Xbox 360

90

12

14.2

175

9

Wii

90

12

3.70

33

10

None

40% of rooms total have game consoles, however all surveyed were male. 1764 total students * (.4 (males on campus) * .5 (males with game consoles)) =.2 total, or 353 game consoles on campus

Used for an average of 90 minutes per day

113.2J/s * 60seconds/minute * 60 mins/hour * 1.5 hours/ day * 365 days/year = 223,117.2 kJ per year per console.

223,117.2 kJ * 353 consoles = 78,760,371.6 kJ

Amy Holmen, mini fridges

Sample

Brand

Votage (V)

Current (A)

Power (W)

1

GE

120

0.75

90

2

MagicChef

115

1.2

138

3

MagicChef

115

1.3

149

4

Sanyo

120

1.0

120

5

Haier

110

1.1

121

6

Danby

120

0.85

102

7

none

--

--

--

8

GE

120

0.75

90

9

none

--

--

--

10

MagicChef

115

1.2

138

AVERAGE

118.5

Yearly Average power use per fridge

Let us assume that the fridge is plugged in and running all day for 9 months of the year (our school year)

118.5 J/sec * 60 sec/1 min * 60 min/1hr * 24 hr/day * 270 day/year= 2.7 *10^6 kJ per year per fridge

Annual Campus Power Use

Assume that 80% of rooms have a fridge, so 750 rooms * 0.80= 600 fridges on campus

2.7*10^6 kJ/year/fridge * 600 fridges= 1.62*10^9 kJ/year

## Homework 3- The basics of biomass (due 2/26/2010)

Some Links to get things started

http://blogs.middlebury.edu/biomass/

http://www.colgate.edu/DesktopDefault1.aspx?tabid=4354

http://www.fs.fed.us/woodybiomass/state.shtml

biomass_memo_071708.pdf

tb197.pdf

http://www.aashe.org/wiki/climate-planning-guide/carbon-offsets.php

http://alethonews.wordpress.com/2010/01/12/up-in-smoke/

Questions to consider:

1) It is generally assumed that Maine is harvesting wood at a rate equal to the annual growth rate.   Is this true?  What are Maine’s requirements for sustainable growth?

2) If question one is true, how does a biomass plant meet the additionally principle for carbon neutrality?  Do we have additional biomass capacity in Maine?

3) Using Middlebury’s wood consumption as a guide, how many acres of forest are required to meet the fuel requirements of the proposed biomass plant at Colby?  How many acres of forest will need to be harvested to meet Colby’s fuels supply in a sustainable fashion?

A) Divide the class into groups of four and decide which group will address which question.

B) Starting with the resources provided at the beginning of this question, generate an annotated bibliography of sources to help answer your question.

C) Generate two figures diagramming the material flows used to help answer your question.

Works Cited

Gibbs, Jeff. "Green Nightmare: Burning Biomass is Not Renewable Energy." The Huffington Post. 17 Dec. 2009. Web. 23 Feb. 2010. <http://www.huffingtonpost.com/jeff-gibbs/green-nightmare-burning-b_b_395553.html>.

The Gibb’s article gives an opposing view, explaining why biomass generated energy is not a renewable energy source.

MaineForest Service. MaineForest Service Assessment of Sustainable Biomass Availability. Rep. Maine State Government, 17 July 2008. Web. 24 Feb. 2010. <http://www.maine.gov/doc/mfs/pubs/pdf/biomass_memo_071708.pdf>.

The Maine Forest Service Report provided information regarding the current biomass of Maine's forests, and the sustainable yield for the forests.

MiddleburyCollege. "Biomass at Middlebury." The Middlebury Blog Network. Web. 24 Feb. 2010. <http://blogs.middlebury.edu/biomass/about/>.

The Middlebury site was used to obtain general as well as specific information regarding the use of biomass technology at MiddleburyCollege. This information was used to determine what would be necessary for Colby to use biomass technology.

National Alliance of Forest Owners. "Carbon Neutrality of Energy from Forest Biomass." Carbon Neutrality of Energy from Forest Biomass. NAFO (National Alliance of Forest Owners), 2009. Web. 23 Feb. 2010. <http://nafoalliance.org/carbon-neutrality-of-energy-from-forest-biomass/>.

The National Alliance of Forest Owners site provides background information in regards to the carbon neutrality of producing energy from forest biomass.

Sarah, Kim, Reuben, and Trevor

## Homework 4 - Due 3/5/2010

Book Problems - Chapter 9: 4, 6, 9, 12, 13

1.  Freon, CFC-12, is building up in the atmosphere at a rate of 1.4 %/year. If the current concentration of CFC-12 is 519 pptv (parts per trillion by volume), what is the net molar flux of CFC-12 to the atmosphere in one year?

2. Calculate the maximum wavelength of radiation that could have sufficient energy to effect the dissociation of nitric oxide (NO). In what regions of the atmosphere would such radiation be available? (The bond energy of NO is 90.2 kJ/mol)

3. The Chapman mechanism of stratospheric ozone production was successful at predicting the shape of the stratospheric ozone concentration profile, but overestimated the ozone concentration.  We now understand that simple ozone models involving only O2, O and O3species are incomplete.  What are the major processes controlling the stratospheric ozone concentration profile (shape and concentration) and how have atmospheric emissions in the last 50 years modified the profile.  (HW Key )

## Homework 5 - Due 4/7/2010

Book Problems 11: 2, 7, 9, 14, 13: 4, 7, 11,17

Additional Problem:  During a recent talk at the Maine Water Quality Conference, Professor Steve Kahl from UMO showed convincing evidence of decreased acid deposition to Maine based on decreasing sulfate concentrations in Maine lakes.  During the same 10 year period the nitrate concentrations have also decreased, but much more slowly.  Explain these findings in terms of the chemistry of “acid rain” including current regulations, atmospheric chemistry, and emission sources.

## Homework 6 - Due 4/16/2010

Lake Problem Set I.

Consider a lake of infinite horizontal dimension, a depth of 20 meters, and a thermoclineat 10 meters. The epilimnetic temperature is 25 oC.    The hypolimnetic temperature is 6oC.   Both layers are well mixed vertically. The alkalinity of the lake is 0.10 mM.

1) Calculate the equilibrium concentration of oxygen at depths of 5 and 15 meters in units of ppm and moles/liter.

2) If the average wind speed on the lake is 10 meters/second, what rate of net biological oxygen demand (moles/liter sec) is required to decrease the oxygen concentration to 90% of saturation at 5 meters?

3) Based on the biological oxygen demand, how long will it take the hypolimnion to go anoxic (<1 ppm O2)?

## Homework 7 - Due 4/23/2010

Lake Problem Set II.

Consider a lake of infinite horizontal dimension, a depth of 20 meters, and a thermocline at 10 meters. The epilimnetic temperature is 25 oC.    The hypolimnetic temperature is 6o C.   Both layers are well mixed vertically. The alkalinity of the lake is 0.10 mM.

1) Calculate the pH of the epilimnion assuming it is in equilibrium with CO2 in the atmosphere.

2) Assuming that the phosphate concentration of the lake was 20 ppb (as P) at the time of the spring turnover, calculate the oxygen concentration in the lake at 5 meters  and 15 meters after all the P in the epilimnion is consumed by photosynthesis, settles, and is respired in the hypolimnion.

3) What is the pH of the hypolimnion after the event described in step 2 occurs?

4)  By how much will the nitrate in the hypolimnion increase after the event described in step 2 occurs?

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1. Hey, I'm interested in working on question 1 if anyone else wants to work on it/meet during class on Wednesday and talk about it.
-Rachael

1. This sounds good, I'll see you on Wednesday

-Greg

2. That sounds great to me too, I'll see you then

2. Yeah I'd like to work on that one with you too, I'll see you on Wednesday!

-Josie

3. Sarah, Kim and I are claiming question 3. We need one additional person in our group. For whoever wants to join, meet in class on Wednesday.

-Reuben

1. Great, I'll see you Wednesday in class

4. So I guess question 2 is left, does whoever not have a group yet want to meet me to work on it in class on Wednesday too?

1. Yea I will see you in class wednesday for number 2