1. Mass of carbon in the atmosphere. (a) The figure below shows the observed sea
ID: 958 • Letter: 1
Question
1. Mass of carbon in the atmosphere.
(a) The figure below shows the observed seasonal cycle of atmospheric CO2 concentration, expressed as a mixing ratio (see note below), in the northern hemisphere. Evidently, there is a decrease of roughly 6 ppm (parts per million) between May and September due to photosynthesis during the northern hemisphere growing season, one of many discoveries Charles Keeling is famous for. Assuming that these measurements are rep- resentative of the global atmosphere, calculate the mass of carbon that this change in CO2 concentration represents. Express your answer in units of petagrams of carbon (PgC). In essence what I
Explanation / Answer
Change in concentration of CO2 from May to September = 6 ppm (parts per million)
From question 1 (Homework 2),
Mass of atmosphere, ma = 5.27 * 1018 kg
Molar mass(average ), M = 28.97 g/mol
Molar mass of CO2 = 44.01 g/mol
Therefore,
No of moles in atmosphere = 1000*5.27 * 1018/28.97
= 1.819 *1020 moles
Concentration of 6 parts per million Carbon Dioxide= number of moles of atmosphere*concentration of CO2 = 6* 1.819 *1020/(106) moles
= 10.914 *1014 moles
Hence mass of change in from May to Septemper, CO2
= Molar mass of C*number of moles
[Since every molecule of CO2 contains one atom of carbon]
= 12.01*10.914 *1014
=131.077* 1014 g
= 13.1077 Pg of C
And also mass of 1ppm of CO2 will be = 13.1077/6 = 2.184 PgC
B)
Hey in this part I need industrial emission data to completely solve it..for now I am only solving overall change in atmospheric CO2 from 1765 to 2010.5 (since last data in file is from 2010.5)
Change in atmospheric CO2 = (Level of atmospheric CO2 in 2010.5 - atmospheric CO2 in 1765)
= (
So change in atmospheric carbon = 2.184 *112.07 PgC =244.7608 PgC
a)
Make a list of the various computers and appliances you use and their power consump-tion. Using this, estimate the amount of (electrical) energy you consume in a year (in
joules). What is your power consumption (in watts)?
For this question I do not know what are the appliances you use, but I will try to give you an idea how to solve it....by explaining my power consumption in an year for few appliances.
Appliances & energy budget yearly: (For that lets make daily estimate of energy consumption)
Phone: It require charging every day for 1 hr average, energy consumed = Power rating * time = 3.68 Watt*1hr =3.68* 3600 Joules = 13248 J= 13.248 kJ
Energy consumed in using laptop daily
Charging required = 4 hrs daily
Power rating = 65 Watt
Thus, Energy consumed in laptop = 65*3.6*4 kJ = 936 kJ
Daily energy consumption = 936+13.248 =949.248 kJ
So total energy budget for year will be = daily energy consumption*365
= 949.248*365 = 346475.52 kJ
Average Power consumption= Energy/time = (949.248/(24*3600))= 10.986 Watts
[You can add as many appliances you want but make sure you record daily energy consumption by that properly, usually appliances come with power rating]
b)
1 Btu = 1055.05585 Joules
Thus electrical energy consumed per year
= 346475520 J
= (346475520/1055.05585) Btu
=
Now since,
Only 30 percent of chemical energy can be converted to electrical energy
chemical energy*0.3 = Electrical energy
=1094651.43 Btu
Energy consumed in mmBtu = 1.0946 mmBtu
COAL:
Amount of coal burnt = energy produced/(per short ton energy produced by coal)
=
=0.0547 short ton of coal is required
FUEL OIL
Amount require = (1094651.43/6287000)
=0.1741 barrel
NATURAL GAS
Amount required = 1000*(1094651.43/1027000) (cubic feet)
=1065.8728 cubic feet
CO2 emission = per unit emission*energy = 56 kg *1.0946 =61.297 kg of CO2
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