When a hydrocarbon fuel is burned, almost all of the carbon in the fuel burns completely to form CO 2 (carbon dioxide). On average, 0.59 kg of CO 2 is produced for each kWh of electricity generated...

When a hydrocarbon fuel is burned, almost all of the carbon in the fuel burns completely to form CO₂
(carbon dioxide). On average, 0.59 kg of CO₂
is produced for each kWh of electricity generated from a power plant that burns natural gas. A typical new household refrigerator uses about 700 kWh of electricity per year.

(1) Determine the amount of CO2 production that is due to the refrigerators in a city with 50,000 households.

(2) If the area of the city is 190 miles², and if all that CO₂
accumulates in the atmosphere, calculate the increase in CO₂
concentration by weight in the atmosphere knowing that each cm²
of area carries a column of air that weighs 1 kg.

(3) If 1 mature tree absorbs 48 lb_m
of CO₂
per year, what is the ratio of trees to households this city should have to counter the effect of refrigeration?