CH217 - Homework
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 Homework Assignment 1: General Chemistry Review (due 2/12/2008)

  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 2/19/2008)

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

Sharon Fuller

microwave

3.73 * 10^4 kJ/year

1077.1

4.01 * 10^7 kJ

Katie Billington

Printer

 

 

 

Mengfei Zhang

desk lamp

6.350*10^8 J/year

1475

9.366*10^8 KJ

Sasha Bartels

mini fridge

6.16*10^16 J/year

933

2.9*10^9 kJ/year

Brittany Tschaen

Television

7.45 *10^7 J /yr

533.4

3.97*10^7 kJ/year

Dan Heinrich

Stereo/Speakers

1.2 * 10^9 J/yr

871

1.04 * 10^9 kJ/yr

Li Yu Chan

cell phone & charger

13.6 * 10^3 kJ

1555.8

2.12 * 10^7 kJ

Brian DiMento

Christmas lights

1.69 * 10^8 J/year

568

9.60 * 10^7 kJ/yr

Rob Dillon

PS2

Running: 6.54 * 10^4 kJ/year

Standby: 3.81 * 10^4 kJ/year

373

3.86 * 10^7 kJ/year

Mischa Noll

iPod

2.07*10^6 J/year

1623

3.36*10^6 kJ/year

Katie Harris

Blow Dryer

3.97E5 kJ

1023.1

4.06*10^8 kJ/yr

Kristina Shiroka

Fan

 

 

 

Elissa Teasdale

Computer/Laptop

9.3*10^5 kJ/year

1875

1.74*10^9 kJ/year

Julia Coffin

Alarm clock

3.28*10^8 J/year

778

2.55*10^8 kJ/year

Lane Mahoney

DVD player

8.9 * 10^3 kJ/year

1120.2

9.97 * 10^6 kJ/year

Cat Zweig

Coffee Maker

 

 

 

Jason Hine

Hair Straightener

5.796 x 10^6 J/year

560.1

3.246 x 10^6 kJ/year

Brynna Patel

N64

3.0*10^4 kJ/year

60

1.8*10^6 kJ/year

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

total

6.5 x 10^9 kJ/yr

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 ....

_______________________________________________________________________________________________ 

Li Yu Chan, Cell phone charger

Sample

Brand

Voltage (V)

Amperes (A)

1

Motorola

5.00

0.85

2

Sony Ericsson

4.90

0.45

3

Black Berry

5.00

0.75

4

Nokia

5.70

0.80

5

Motorola

5.10

0.80

6

Nokia

5.30

0.50

7

Unbranded

5.00

0.60

8

Sony Ericsson

4.90

0.45

9

Samsung

5.00

0.70

10

Motorola

5.00

0.85

Average

-

5.09

0.68

 Average Power = 5.09 * 0.68 = 3.46 W
[DWK: Watch your order of operations in the average power calculation. The average power is not the same as the average voltage x average amps. However in this case it will be close]

Average energy consumption per year, assuming 3 hours daily use = 3.46 J/sec *60 sec/min * 60 min/hr * 3 hr/ day * 365 days = 13.6 *10^3 kJ

Total Energy based on probability that 10/12 students have cell phone chargers = (13.6*10^6) * 10/12* 1867 = 2.12*10^7 kJ

___________________________________________________________________________________________________________________ 

Katie Harris, Blow Dryer

 

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

___________________________________________________________________________

 Sharon Fuller, microwave

 120V * 7.5A = 900W

Average energy consumption per year assuming 3 minutes daily use: 

900 J/sec * 60 sec/min * 3 min/day * 230 day/year = 3.73 * 10^7 J = 3.73 * 10^4 kJ

With 15 microwaves per 26 students in survey:

3.73 x 10^4 kJ * 1867 students * (15/26) = 4.01 * 10^7 kJ

_____________________________________________________________________________

Brian DiMento, Christmas Lights

120V * 0.34A = 40.8W

Energy consumption assuming 5 hours of daily use, over an academic year (approximately 230 days on campus):

40.8 J/sec * 60 sec/min * 60 min/hr * 5 hr/day * 230 day/year = 1.69 * 10^8 J/year

Survey: 7 100 bulb strands found per 23 students.

1.69 * 10^8 J * 1867 students * (7/23) =  9.60 * 10^10 J total


Mengfei Zhang, Desk Lamp

sample number

Power

Time of use per year

Energy consumed per year

1

20w

52hr * 3600s/hr=187200s

3.744*10^6 J

2

20w

2184hr * 3600s/hr=7862400s

1.572*10^8 J

3

60w

104hr * 3600s/hr=374400s

2.246*10^7 J

4

40w

1092hr * 3600s/hr=3931200s

1.572*10^8 J

5

60w

104hr * 3600s/hr=374400s

2.246*10^7 J

6

60w

520hr * 3600s/hr=1872000s

3.744*10^7 J

7

60w

52hr *3600s/hr=187200s

1.123*10^7 J

8.

75w

208hr * 3600s/hr=748800s

5.616*10^7 J

9.

13w

208hr * 3600s/hr=748800s

9.734*10^6 J

10.

60w

676hr * 3600s/hr=2433600s

1.460*10^8 J

11.

60w

520hr * 3600s/hr=187200s

1.123*10^7 J

 

 

 

 

Average energy consumed per year by one desk lamp:

(3.744*10^6+1.572*10^8+2.246*10^7+1.572*10^8+2.246*10^7+3.744*10^7

+1.123*10^7+5.616*10^7+9.734*10^6+1.460*10^8+1.123*10^7)J /11 =6.350*10^8J=6.350*10^5 KJ

In the survey, 79% students use lamps, and each uses one. Number of students on campus is 1867. Number of desk lamps on campus : 79%*1*1867=1475

Total energy consumed: 6.350*10^5 KJ * 1475= 9.366*10^8 KJ

                                                                                                                                                                                   

Julia Coffin, Alarm clock

15V*1.1A=16.5W

Energy consumption is assuming the alarm clock remains plugged in, over an academic year (approximately 230 days on campus)

Energy Consumption: 16.5 J/sec * 60 sec/min * 60 min/hr * 24 hr/day * 230 day/year = 3.28*10^8 J/year

In the survey: Number of students on campus is 1867. Number of alarm clocks on campus : (41.67%/100)*1867=778 alarm clocks

Survey: 5 alarm clocks found per 12 students sampled.

Total Energy Consumption: (3.28*10^8) J/year * 1867 students * (5/12) =  2.55*10^11 J/year total

                                                                                                                                                                                   

Sasha Bartels, minifridge

120V*1.3A=156W

fridge remains plugged in constantly for the 230 days on campus

Energy Consumption: 156 J/sec * 60 sec/min * 60 min/ hr * 24 hrs/day * 230 days/year = 3.1*10^9 J/year

In survey, found about 1 minifridge per 2 people. 1867 students/2=933 minifridges on campus

Total Energy Consumption on campus: 3.1*10^9 J/year * 933 minifridges= 2.9*10^12 J/year 


Dan Heinrich, stereo/speakers
 Average speaker wattage surveyed from 15 students, 60 W.

7/15 students had speakers, .47 * 1867 students = 871 stereos

Averaging 30 min of daily use for 230 days on campus a year.

Energy Consumption: 60 J/s * 60 s/min * 60 min/hr *24 hrs/day * 230 days/yr =  1.2 * 10^9 J/yr per stereo

Total Energy Consumption at Colby for stereo use: 1.2 * 10^9 J/yr * 871 stereos = 1.04 * 10^12 J/yr = 1.04 * 10^9 kJ/yr

----

__________________________________________________________________________________________________________________________________

Mischa Noll, iPod

iPod wattage: 5.0 V * 1.0 A = 5.0 W

20/23 surveyed students had ipods, therefore this translates to 86.95% or 1623 Colby students.

If used 30 minutes a day on average, (5 J/s)(60 s/min)(30 minutes)=9,000 J/person/day

Since 230 days are spent on campus each academic year, (*230) there are 2.07*10^6 J/person/year

 Multiply this by the 1623 students and we get 3.36*10^9 J/year or 3.36*10^6 kJ per year used at Colby


Elissa Teasdale, Laptop

Sample

Voltage (V)

Amperes (A)

 Power (W)

1

19.5

4.62

90.09

2

18.5

4.6

85.1

3

18.5

4.6

85.1

4

19.5

4.62

90.09

5

16.5

3.65

60.225

6

15

5

75

7

14.8

6.6

97.68

8

14.8

6.6

97.68

9

18.5

4.6

85.1

10

24

1.875

45

Average

 

 

81.10

100% of the students surveyed owned and used their laptops. The energy consumption calculation is based off of the average hours the laptop was plugged in per day (13.9 hours) by the students surveyed for throughout the academic year (approximately 230 days). The number of students on campus = 1867.

Energy Consumption: (81.1 J/sec)(60 sec/min)(60 min/hr)(13.9 hr/day)(230 days/1 academic year) = 9.3*10^8 J/year = 9.3*10^5 kJ/year

Total Energy Consumption of laptops by students on campus: (9.3*10^8 J/year)(10/10)(1867 students) = 1.74*10^12 J/year = 1.74*10^9 kJ/year

                                                                                                                                                                                                                                             

Brynna Patel, Nintendo 64

30 people asked-- 3 machines

Multiple people only need one machine-- about 60 on campus

Average time played per day: 1.375 hours

Machine uses 26 watts so.....

     Energy Consumption: (26 J/sec)(60 sec/min)(60 min/hr)(1.375 hr/day)(230 days/1 academic year) = 3.0*10^7 J/year or 3.0*10^4 kJ/academic year

     Total Energy Consumption (during one academic year at Colby): (3.0*10^4 kJ/year)(60 machines on campus) = 1.8*10^6 kJ/academic year


Rob Dillon, PS2

 

W

kJ/hr

avg hrs used/day

avg hrs used/academic year

kJ/year

Running

79

284.4

1

230

6.54*10^4

Standby

2

7.2

23

5290

3.81*10^4

 Energy Consumption:

 Running: (79 J/sec)(1 kJ/1000 J)(60 sec/min)((60 min/hr)(1 hr/day)(230 days/1 academic year) = 6.54 * 10^4 kJ/ year

 Standby: (2 J/sec)(1 kJ/1000 J)(60 sec/min)((60 min/hr)(23 hr/day)(230 days/1 academic year) = 3.81 * 10^4 kJ/ year

 While running the PS2 uses 79W and while its on standby it uses 2W.  20% of the students surveyed owned a PS2. The total # of students is 1867. Total students with PS2 is 373.

Total Energy consumption of PS2 by students:

Running:  (6.54*10^4 kJ/ year)(373 students) = 2.44*10^7 kJ/year

Standby:  (3.81*10^4 kJ/year)(373 students) = 1.42*10^7 kJ/year          Total: 2.44 + 1.42 = 3.86 * 10^7 kJ/year


Brittany Tschaen, Television

120V * .75A = 90W

Average energy consumption per year assuming 1 hour daily use: 

90 J/sec * 60 sec/min * 60 min/hr * 1 hr/day * 230 day/year = 7.45 *10^7 J/year = 7.45 * 10^4 kJ/year

Survey Results: 6 microwaves per 21 students

7.45 * 10^4 kJ/year * 1867 students * (6/21) = 3.97 * 10^7 kJ/year


Lane Mahoney, DVD player
DVD player wattage: 15 W

Energy Consumption per year assuming 5 hours weekly use and 33 weeks at Colby:

(15 J/sec) (60 sec/min) (60 min/hr) (5 hr/week) (33 weeks/year) = 8.9 x 10^6 J/year = 8.9 x 10^3 kJ/year  

Number on Campus: Surveyed 10 rooms, 5 singles and 5 doubles: found that for every 15 students there are 9 DVD players

(3/5) (1867 students) = 1120.2 DVD players on campus

Total Energy Consumption per year at Colby:

(8.9 x 10^3 kJ/year) (1120.2 DVD players) = 9.97 x 10^6 kJ/year 


Jason Hine, Hair Straightener

Sample

watts

1

150

2

120

3

100

4

150

5

95

6

85

average wattage = 116.67 W

average usage = 3.6 min/day

 33 weeks a year at Colby

116.67 J/s * 60 sec/min * 3.6 min/day * 230 days/year = 5.796 x 10^6 J/year

6 straighteners per 20 students, 1867 students at Colby

5.796 x 10^6 J/year * 1867 students * (6/20) = 3.246 x 10^9 J/year

Homework Assignment 3:  The Hybrid Car (due 2/21/2008)

    Using the US DOE Hybrid vehicle cost calculator, compare the lifetime cost of running a hybrid vehicle versus a conventional vehicle of the same size.   Each group of four students should select a different vehicle size class.   Use current fuel prices, a 10 year vehicle lifetime, and an annual millage of 15,000 miles.   The hybrid vehicles will save gasoline and, therefore, reduce carbon dioxide emissions.  How much would it cost to purchase carbon credits to offset the increased gasoline consumption of a conventional powered car?  How would purchasing carbon credits change the economics of running a hybrid versus a conventional car?  Please show your work and provide details on your calculations.

 Group Assignments for this assignment:

Group I
 Hine, Jason F.
 Chan, Li Yu
 DiMento, Brian P.
 Shiroka, Kristina A.
Group II
 Zhang, Mengfei
 Noll, Michael S.
 Bradley, Sharonda Q.
 Fuller, Sharon R.
Group III
 Dillon, Robert W.
 Billington, Kaitlyn E.
 Bartels, Sarah E.
 Patel, Brynna M.
Group IV
 Teasdale, Elissa L.
 Zweig, Catherine E.
 Melese, Mesay
 Harris, Katie
Group V
 Tschaen, Brittany A.
 Mahoney, Lane J.
 Heinrich, Daniel G.
 Coffin, Julia P.


Post answers to assignment 2 below:  (list names of group members at the beginning of each question).
Your answer should be in narrative form with links to external data sources and specifics on any calculations.  Each student in the group should contribute to the answer. This assignment is only submitted on this page.

[Tschaen, Brittany A., Mahoney, Lane J., Heinrich, Daniel G., Coffin, Julia P.]

Vehicle Class: Midsize Sedan

Car data taken from the  DOE Hybrid Vehicle Cost Calculator:

Hybrid Vehicle: Lexus GS 430h = cumulative cost $61,920

Conventional Vehicle: Lexus GS 450 = cumulative cost $52,088

Hybrid lifetime emissions savings from carbon dioxide= 29,880 lbs

Cost of Carbon Credits = $75.00 from www.carbonfund.org for 30,000 lbs.

Final Hybrid Vehicle Cost: $61,920.

Final Conventional Vehicle Cost: $52,088 + $75.00 = $52,163.

As of now, it is still more economical to purchase a conventional vehicle and carbon credits than to purchase a hybrid vehicle.  In fact, one would save $9,757 if they were to purchase carbon credits and a conventional vehicle (61920-52163) and be equally green.


Dillon, Rob / Bartel, Sasha / Patel, Brynna
Vehicle Class: SUV

Hybrid Vehicle: Ford Escape (hybrid model) / cumulative cost = $37,525.44

Conventional Vehicle: Ford Escape / cumulative cost = $36,745.12

Hybrid Lifetime emissions savings from CO2 = 24,624 lbs.

Cost of Carbon Credits =  30,000lbs Carbon Offset - $148.50 from www.terrapass.com

Final Hybrid Cost: $37,525.44

Final Conventional Cost:  $36,745.12 + $148.50 = $36,893.62

It is still more economical to buy the conventional vehicle and carbon credits based on our comparison. You would save a little under $1,000 over the hybrid.

____________________________________________________________________________________________________________________________________________________________

Teasdale, Elissa & Harris, Katie

Vehicle Class: Small Car

Hybrid Vehicle: Toyota Camry               cumulative cost =$34,755.36

Conventional Vehicle:  Toyota Camry              cumulative cost=$32,673.34

Hybrid Lifetime emissions savings from carbon dioxide =  31,239lbs.

Cost of carbon credits = $5.50/ton (http://www.carbonfund.org/)  31,239/2000 * 5.50 = $85.91

Final Hybrid Cost =$ 34,755.36

Final Conventional Cost =  $ 32,673.34 + $85.91    = $ 32,759.25

Fuel Price $3.02 (http://tonto.eia.doe.gov/oog/info/gdu/gasdiesel.asp)

Economically it makes sense to buy a conventional Toyota Camry. It's as equally good for the environment to buy equal carbon credits that you would save from the lifetime emissions from a hybrid. In fact you save about $2000.


Brian DiMento, Li Yu Chan, Jason Hine

Vehicle Class: Pickup Truck

Car data taken from the  DOE Hybrid Vehicle Cost Calculator:

Hybrid Vehicle: Chevrolet Silverado 1500HD Cls = cumulative cost $52,086.27

Conventional Vehicle: Chevrolet Silverado 1500 = cumulative cost $50,006.27

Hybrid lifetime emissions savings from carbon dioxide= -19,866 lbs.

Cost of Carbon Credits = $99.00 for 20,000 lbs carbon offset (www.terrapass.com)

Final Conventional Vehicle Cost: $50,006.27

Final Hybrid Vehicle Cost: $52,086.27 + $99.00 = $52185.27

Fuel Price: $3.04  (http://www.eia.doe.gov/oil_gas/petroleum/data_publications/wrgp/mogas_home_page.html)

City Driving: 50% of the time 

 It is more economical to purchase a conventional truck than a hybrid.  Over its 10 year lifetime, it would cost $2179.00 more to own the hybrid truck (after buying carbon credits). The hybrid truck actually produced more carbon than the conventional truck, potentially because of its larger engine that resulted in a lower mpg.  Because of this, the hybrid truck owner would be the one buying the credits.  There were no exactly comparable trucks in this class to test to avoid this conclusion.

___________________________________________________________________________________________

Fuller, Sharon; Zhang, Mengfei; Noll, Mischa

Vehicle Class:Sedan Driven 25,000 miles per year

Fuel Cost: $3.05/gallon

Hybrid Vehicle:  Toyota Camry Hybrid                  cumulative cost =$45,449.96

Conventional Vehicle: Toyota Camry                cumulative cost=$45,779.05

Hybrid Lifetime emissions savings from carbon dioxide = 52,064 lbs.

Cost of carbon credits = $5.50 per ton (www.carbonfund.org) * 52,064 lbs/2000 = $143.18

Final Hybrid Cost =$45,449.96

Final Conventional Cost =  $45,779.05 + $143.18    =$45,922.23

Even before purchasing carbon credits, it is cheaper to get the hybrid camry. By driving the car longer distances, it becomes worth it to invest the extra couple of thousand dollars in the beginning.

Homework Assignment 4:  Book Problems (due 2/28/2008)

Please hand in your solutions to book problems:  Problem set I: 1, 2, 6, 8, 9, 12, 19, 22, 23, 24, 25 

 Answers to problems: 

1d 5.57x10^9 kJ

2  10^16 tons

6  57% as efficient

8  about the same

9 coal mass flow 766 kg CO2, 11.6 kg SO2

12  1.4x10^16 inonizations/yr

19c $15825

22 

23  6 times the volume

24c 175 percent

25 68%

Solutions

Homework Assignment 5:  Due 3/11/2008

Book Problems: page 242: 2, 4, 8, 10, 20, 21, calculate the pressure and mixing ratio of oxygen and nitrogen in the atmosphere at 2,000, 4,000, and 10,000 meters altitude. Book questions, pressure calculation

Prepare two questions to ask our speaker on 3/11.   Be prepared to ask your question, if appropriate, at the end of Prof. Rowland's talk.   We will follow the Department of Chemistry three question rule - the first three questions of a seminar must be from students.   You will turn your questions with your homework at the end of class. 

Homework Assignment 6: Due 3/20/2008

A significant source of CFCs to the atmosphere is through their use as refrigerants in air conditioning systems and subsequent leakage to the atmosphere.    Colby is making an effort to reduce the emission of CFC (or HCFCs) by designing new building to LEED specifications that require carefully designed air conditioning systems.   LEED is a building standard used by the US Green Building Council to reduce the environmental impact of construction.  For the purposes of this homework assignment, lets assume Colby is renovating Treworgy next year and want to install air conditioning.   Treworgy has about 5000 ft^2 of space and would require (love the units) 10 tons of compressor capacity to meet the cooling requirement of the building.  Assuming a 10 ton AC unit will contain 70 lbs of refrigerant, is it possible to make the AC installation LEED certified?  After reading the attached links use the CFC calculator from Trane to calculate the LEED credit (or not) for the air conditioning unit you choose.  What are the trade-offs between different refrigerant types?

Resources: LEED Certification (page 39) OR, only the CFC LEED section.  Details on the  Refrigeration cycleChillers from Carrier Corp, and LEED CFC Calculator from Trane in MS Excel format.

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