Group Exercise Three Solution Part a: 1.8 mmol CO2/kJ x 10,000 kJ, x 4 persons x 365 days x 44.01 g CO2/mol x 1 mol/1000 mmol = 1.156 x 10^6 grams per year for four persons. Part b: 15,000 miles x 1 gal/20 miles x 4 qts/gal x 1 L/1.057 qt x 0.7025 g/mL x 1000 mL/L x 1mol octane/114.23 g x 8 mol CO2 / 1mol octane x44.01 g CO2/molCO2 = 6.145 x 10^6 g CO2/year. Part c: 1200 kwh/mo x 12 mo/yr x 3.6 x 10^6 J/kwh x 1/0.20 (the efficiency factor, needed in this problem) x 1 mol CH4/802 kj x 1 kJ/1000 J x 1 mol CO2/mol CH4 x 44.01 g CO2/mol CO2 = 1.42 x 10^7 g CO2/year. Part d: Breathing: 1.156 x 10^6 g CO2 /4 person years Automobile: 6.145 x 10^6 g CO2 /4 person years Electricity: 14.2 x 10^6 g CO2 /4 person years Total: 21.5 x 10^6 g CO2 /4 person years From figure of 1.0 x 10^6 kJ consumed per person per day: 1.0x10^6 kJ/day x 4 persons x 365 days x 1mol CH4/802 kJ x 1 mol CO2/mol CH4 x 44.01 g CO2 /mol = 8.01 x 10^7 g CO2/4 person years (or 80.1 x 10^6) Therefore, breathing , driving, and electricity account for about 27% of our use of energy. Part e: 8.01 x 10^7 g CO2 x 1 mol CO2/g CO2 x 10 yrs x 1/4 persons = 4.55x10^6 moles of CO2 per person in 10 years. volume of atmosphere = 1.0 x 10^22 liters 1.0 x 10^22 L x .022 moles/L x 1 mol CO2/10^7 moles air (for 0.1 ppm) = 2.2 x 10^13 moles. 2.2 x 10^13 moles/4.55 x 10^6 moles/person = 4,830,000 people in ten years (or 48 million people in one year)