Hence no one in the science section helped me I decided to come here. Anyways, the problems are just basic math.[/B]
1 )A gallon of gasoline carries with it about 1.3*10^8 J of energy. Given a price of $3 per gallon, how many Joules can you get for a dollar?
2)Electricity goes for about $0.05 per kilowatt hour. A kilowatt hour is just a weird way to write Joules because a watt is a joule per second, and a kilowatt hour is the number of Joules one would get from running 1000 W times one hour (3,600 seconds). In the form of electricity, how many Joules can you get for a dollar?
3)A standard cubic foot of natural gas carries with it about 1.1 x 106 J of energy. You can get about 5 x 105 British thermal units(BTUs) of gas for a dollar, and there are about 1,030 BTUs in a standard cubic foot. How many Joules of energy in the form of natural gas can you get for a dollar?
4)A ton of coal holds about 3.2 x1010 Joules of energy and costs about $40. How many Joules of energy in the form of coal can you get for a dollar?
5)Corn oil costs about $0.10 per fluid ounce wholesale. A fluid ounce carries about 240 dietary calories (which a scientist would call kilocalories). A calorie is about 4.2 Joules. How many Joules of energy in the form of corn oil can you get for a dollar?
6)Rank these as energy sources,cheap to expensive. What is the ratio in cost per Joule between the most expensive and the cheapest form?
The Attempt at a Solution
1) 1.3*(10^8)/3= 4.3*10^7
so electricity goes $0.05/3.6*10^6 J
for 1 dollar= 20*3.6*10^6 J=7.2*10^7 J
3)(5*10^5 BTUS/ 1030 BTUS)*(1.1*10^16)= 5.3*10^8 J
4)(3.2*10^10)/40 = 8*10^8
6 Coal, natural gas, electricity,gasoline, corn oil
Based on the choices, Corn coil is about 10 times more expensive than coal.