CH217 - Homework
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 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

 

 

 

Andy

Laptop chargers

 

 

 

Reuben

Televisions

 

 

 

Erin

Hair Straighteners

 

 

 

Rachael

Lamps

9.58 E7 J/yr

1717

1.65 E8 kJ

Amy

Refrigerators

 

 


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

 


 

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

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