Fossil Fuels
What is primary purpose of coal?
Generating electricity
Oil
What is the purpose of a hydrogen fuel cell?
It converts the chemical energy is hydrogen fuel into electricity.
The biggest downside of solar is __________
Intermittence. Sunlight is only available during the day and is decreased significantly on cloudy days.
A 10 W lightbulb is left on for 20 seconds. How many joules of energy does it use in that time?
10W x 20s = 200 J
What are the primary reactants and products of a combustion reaction?
Fuel and oxygen react to form carbon dioxide and water vapor
Fracking led to a huge increase in natural gas supply which did what to the price of natural gas?
Price decreased
Describe how a traditional coal-fired power plant generates electricity.
Coal is burned to generate heat which is used to boil water. The expanding steam is used to push a turbine which runs a generator in order to convert the kinetic energy of the turbine into electricity.
In order to generate power with geothermal energy, where must you be?
Near a convergent or divergent tectonic plate boundary or above a hotspot
A 50 W microwave is left on for 1 hour. How many kWh of energy did it use in that time?
50 W = 0.05 kW
0.05kW x 1h = 0.05 kWh
Natural gas and crude oil mainly form from the remains of what type of organism?
Plankton
Global energy consumption has been rapidly increasing over the last 100 years because of what two reasons?
Population growth and increased per capita energy-use due to economic and technological growth
Hydraulic fracking uses high-pressure water to fracture layers of shale to extract natural gas, but the downside is that ____________.
Due to a leak or improper disposal of fracking water, surface or groundwaters can be contaminated.
Give one advantage and one disadvantage of wind power
Advantages: wind is renewable, non-depletable, clean, cheap and can share land with other uses
Disadvantages: wind has a low output, it's intermittent and unreliable, contributes to the death of some wildlife, and is considered a nuisance by locals.
If a 1200 W hairdryer is used for 10 minutes each day, then how many kWh of energy would be used in total over the course of a whole week?
1200W = 1.2 kW
1 week = 70 min = 1.16 hours
1.2 kW x 1.16 h = 1.4 kWh
Identify two advantages that methane has over coal as an energy source.
Methane burns "cleanly" (less CO2 and no other contaminants)
Gases are easier to transport and process than solids
Methane combustion results in more kWh/kg of fuel burned
Identify one strategy that governments can use to ensure country-wide energy conservation.
Mandating high fuel economy standards
Mandating standards of insulation for buildings
Subsidizing efficient means of energy production such as natural gas
Investing in public transportation
Using a variable price model for electricity
What malfunction led to the meltdown of the reactor core in the case of Chernobyl, Three Mile Island, and Fukushima?
A failure in the coolant-pumping system led the reactor core to be deprived of coolant and overheat.
This form of renewable energy is not originally derived from sunlight
Geothermal
If the output of a gas-powered power plant is 900 MW of electricity, and the efficiency is 60%, then what is the initial rate of thermal energy production during the combustion process?
900MW / 0.6 = 1500 MW
List the four substances in chronological order that comprise the steps of coal formation
Peat, lignite, bituminous coal, anthracite
People in less developed countries rely primarily on what type of energy source?
Subsistence fuels (type of biomass)
This word describes when a system which uses thermal energy to generate power is able to utilize some of the waste heat to do something useful like producing hot water or heating a building.
Cogeneration
Hydrogen fuel cells generate electricity very efficiently and the fuel itself is very light. Despite this, why are hydrogen-powered cars rarely used over conventional electric vehicles?
Hydrogen fuel has to be created which costs money and energy. This drastically decreases its overall efficiency when the whole supply chain is taken into account.
If the half-life of a radioactive substance is 2 years and a sample of this substance is allowed to decay for 12 years, then what fraction of the original substance will be left?
12 years is 6 half-lives so 1/64 of the material will remain
During fractional distillation at a refinery, crude oil is separated into its constituent hydrocarbons by taking advantage of what?
The different boiling temperatures of hydrocarbons
Global carbon emissions from transportation and our dependence on petroleum is a big environmental problem. Give one reasons why electric cars are NOT a perfect solution to this problem.
Electricity to power EVs usually comes from burning fossil fuels
Many of the components to make EVs comes from petroleum or natural gas
Many vehicles such as aircrafts cannot be electrified and must run on fuel
This type of powerplant uses mirrors to capture solar energy and generate a large amount of heat.
Concentrated Solar Thermal Array
How do hydroelectric dams impact the physical and chemical characteristics of water on either side?
Water on the upstream side becomes still, warm, nutrient-dense, and oxygen-deficient (eutrophic) whereas the downstream flow lessens and becomes nutrient-starved.
You drive 30 miles/day on average, and the fuel economy of your car is about 20 miles/gallon. If the average cost of gasoline is $3.85/gallon, then how much money will you spend on gasoline over a period of 5 years?
30 miles/day x 365 days/year x 5 years = 54,750 miles
54,750 miles / 20miles/gallon = 2,738 gallons
2,738 gallons x $3.85/gallon = $10,539