unit 6 exam apes

Convert 27.30 joules to kilojoules.

0.0273kJ

If an incandescent light bulb used for lighting has an efficiency rating of 5 percent, then for every 1.00 joule of electrical energy consumed by the bulb, which of the following is produced?

0.05 joule of light energy

If an incandescent lightbulb used for lighting has an efficiency rating of 5 percent, then for every 1.00 joule of electrical energy consumed by the bulb, how much energy is actually being used?

0.05joules

A home uses ten 100-watt lightbulbs for five hours per day. Approximately how many kilowatt-hours of electrical energy are consumed in one year by using the lightbulbs?

1 kw = 1000 w 100 watt light bulbs= 0.1 watt light bulbs 0.1 x 10 light bulbs= 1 kw of energy used by all of the lightbulbs in 1 hour 1 x 5 hours a day= 5 kw of energy used by the light bulbs in 5 hours 5 x 365 days in a year= 1,825 kilowatt hours of electrical energy

The half-life of radon gas is approximately four days. Four weeks after the introduction of radon into a sealed room, the fraction of the original amount remaining is closest to what?

1/128

The half-life of carbon-14 is 5715 years. If an animal bone contains 20 grams of carbon-14 when the animal dies, how many grams of carbon-14 will be left in 17145 years?

2.5 g

Burning one gallon of gasoline in a car releases approximately 20 pounds of CO2 into the atmosphere. One person drives 60,000 miles in a car that averages 30 miles per gallon (mpg), while another person drives 60,000 miles in a car that averages 20 mpg. Over the course of the 60,000 miles, how many fewer pounds of CO2 are released by the 30 mpg car than by the 20 mpg car?

20,000

A 2.5 gram sample of an isotope of Strontium-90 was formed in a 1960 explosion of an atomic bomb at Johnson Island in the Pacific Test Site. The half-life of Strontium-90 is 28 years. In what year did only 0.625 grams of this Strontium-90 remain?

2016

A sample of radioactive waste has a half-life of 10 years and an activity level of 2 curies. After how many years will the activity level of this sample be 0.25 curie?

30 years

In 1997 the World Resources Institute estimated the world's proven oil reserves to be 1,000 billion barrels and the ultimately recoverable reserves to be 2,000 billion barrels. The table below shows the world consumption of oil from 1986 to 1997. At the 1997 rate of consumption, about how long will the estimated 2,000 billion barrels of oil last?

37 years

With moderate winds, a modern large wind turbine can generate about 250 kW of electricity, whereas a large nuclear power plant can generate 1,000 MW. How many wind turbines would be required to give the same output as one nuclear power plant?

4,000 wind turbines would give the same output as one nuclear power plant.

An isotope of Cesium-137 has a half-life of 30 years. If 35.0 mg of Cesium-137 disintegrates over a period of 90 years, how many mg of Cesium-137 would remain?

4.375 mg

If an incandescent light bulb used for lighting has an efficiency rating of 5 percent, then for every 1.00 joule of electrical energy consumed by the bulb, how much energy is used?

5% of 1.00 joule = 0.05 joules of light energy

After 200 million years, only 1/16 of the original amount of a particular radioactive waste will remain. The half-life of this radioactive waste is how many million years?

50 million years

Convert 5.50 kilojoules. Then to calories. 1 cal = 4.2J.

5500 J & 1309.5 cal

How much would it cost to operate a refrigerator for one year given that it uses 6 kWh/day and the cost of electricity is 18 cents/kWh?

6 kWh/ day * 365 days/year * .18 cents/ kWh = $394.20

Given that the electricity for home use is 5 cents per kilowatt-hour (kWh), how much would it cost to operate 5 fluorescent 40W light bulbs for the months of April and May if they are on for 3 hours/day? How much less is this than running 5 incandescent 100W light bulbs for 3 hours/day over the same time period?

61 days for 3 hours per day = 183 hours total * 5 Light bulbs = 915 hours / 40 watts = 22.875 * 0.05 = $1.83 for fluorescent 4.58 for incandescent and you have 2.75 saved

If the annual consumption of petroleum in the United States is about 23 barrels per capita, what is the total annual consumption of petroleum in the United States?

7.6 billion barrels

An individual has been driving a passenger vehicle to work, averaging 60 miles a week in a car that averages miles 22 per gallon. The individual plans to purchase a hybrid vehicle that averages 50 miles per gallon. If the individual drives to work 50 weeks a year, how much gas will they save if they switch to a hybrid vehicle for their commute?

76 gallons

If the half-life of Francium-233 is 22 minutes, how much time must elapse in order for 60 grams of a 64 gram sample to undergo decay? In other words, after how many minutes will you only have 4 grams of the original isotope remaining?

88 minutes

Give an example of cogeneration.

A coal powered heat uses energy to heat adjacent buildings

Describe an environment where large amounts of oil could form millions of years in the future.

A river delta in a forested region

Some solar energy systems produce high-temperature water for industrial applications and produce steam to run turbines that generate electricity. What type of solar energy system is needed for these kinds of applications?

A solar collector system using mirrors or lenses to concentrate sunlight.

Scientists are looking for new locations to generate electricity using geothermal energy. Where would be the best choice for a geothermal energy generating plant?

Along plate boundaries.

What would be the best location for a wind farm with ten industrial turbines?

Arranged uniformly on a local farm that has fields and pasture land for dairy and grain productive. In the ocean or in the side of a hill or valley.

What common substances are derived from petroleum?

Asphalt, DDT (pesticide), polystyrene (plastic), and nylon.

Explain the process of electricity generation in a hydrogen fuel cell.

At the anode, hydrogen is oxidized and electrons flow in a circuit to the cathode. At the cathode, oxygen reacts with the hydrogen to produce water. Water and heat are by-products of the reaction.

Why are gas prices different in different states?

Availability, price, and governmental regulations influence which energy sources people use and how people use them.

Which rock layer that can be porous but must have very low to no permeability?

B

Batteries are usually rated in terms of ampere-hours, indicating the current that the cell is capable of delivering for a specified time. A typical D-cell flashlight battery, for instance, might be rated at 3 ampere-hours. The total electrical energy available from such a battery is found by multiplying the ampere-hour rating by the battery voltage. Thus this same 1.5 volt D cell could deliver 4.5 watt-hours of electrical energy. Convert this energy to kWh and compare the cost of electrical energy derived in this manner to that of standard "grid-based" electricity. Assume that the battery costs $1.00 and that electricity from the power company is available at $0.10/kWh

Battery energy: 4.5 Wh = 4.5 x 103 kWh. Cost per kWh: $1.00 / 4.5 x 103 kWh = $222/kWh. Comparison: Electrical energy from the battery costs $222 / $0.10 = 2,220 times as much as that delivered by the power company.

In the majority of less developed countries, the major source of energy for domestic use is what energy source?

Biomass

What is an advantage of burning biomass rather than burning fossil fuels in developing countries?

Biomass production is cheaper than fossil fuel extraction, making it more readily available for use.

The separation of the various components of crude oil in refineries is accomplished primarily by taking advantage of differences in what?

Boiling points.

Which rock layer must be porous and have enough permeability for fluid to move through the layer?

C

Describe an environmental problem that can result from the combustion of fossil fuels to generate electricity.

CO2 is a produce of the combustion of fossil fuels, it can lead to global climate change when it's released into the atmosphere

Describe an advantage of burning biomass rather than burning fossil fuels in developing countries?

Cheaper than fossil fuel extraction and more readily available for use.

The largest hydroelectric dam in the world is located on one of the world's longest rivers in which country? Give the letter and name it.

China: Letter E. The Three Gorges Dam

What are the top 3 energy sources globally?

Coal, oil, and natural gas.

Hydraulic fracturing, or fracking, is the pumping of highly pressurized water with a mixture of sand and chemicals into boreholes to do what?

Create cracks in rocks. This provides a pathway for natural gas to escape and be pumped out

Which rock layer must be rich in organic matter that was subjected to heat and pressure over time during the formation of oil and natural gas?

D

Buildings designed to partially heat rooms by passive solar heating rely on what?

Dark materials that absorb the sun's energy.

Describe the conditions under which peat is formed?

Decayed vegetation placed under high pressure, anaerobic and acidic conditions.

What is one solution for reducing the amount of atmospheric carbon dioxide?

Decreasing the use of fossil fuels.

What was the primary cause for the decline in the use of wood as a fuel in the eighteen hundreds?

Deforestation

Advantages of Nuclear Energy

Does not produce greenhouse gas such as CO2

How can you mitigate the production of particulates indoors, which can be a health hazard to humans?

Find better ventilation or filtration systems.

What is the most successful solution to the problem of fish mortality caused by dams?

Fish ladders.

What process would provide the energy used to generate electricity at a power plant?

Fission of the nuclear material.

This type of energy utilizes heat that is stored beneath Earth's surface to heat water and produce steam. What is it?

Geothermal Power

Describe a disadvantage of geothermal energy production.

Geothermal energy implementation in homes and businesses has a high upfront cost, and electricity is needed to operate pumps. Noise and corrosive chemicals being released into the environment.

What energy source is not derived directly or indirectly from solar energy?

Geothermal energy.

Describe an environmental problem associated with hydraulic fracturing, or fracking.

Groundwater contamination. Fracking fluids can escape from the hole and contaminate surface and groundwater.

Throughout the world, especially the less-developed countries, burning wood or other biomass for heating or cooking in homes is common. One negative environmental impact of this practice is the production of particulates indoors, which can be a health hazard to humans.What is the best strategy for mitigating this potential problem?

Increasing ventilation.

A developer intends to use passive solar heating in a new construction project in Minnesota in an effort to reduce electricity costs for the property owners. What should be employed to maximize the benefit of passive solar heating?

Install south-facing glazed windows in the home and dark surfaces to cover the walls and floors.

Many environmentalists consider Egypt's Aswan High Dam on the Nile River to be an ecological disaster. Why?

It caused most of the nutrient rich silt that the Nile annually deposited downstream to be deposited behind the dam, therefore, robbing the downstream solids of its fertility.

What is an advantage of using natural gas, rather than oil, as a fuel is that natural gas?

Less pollution Less money

The water used in a nuclear power plant is often released back into a reservoir. What effects could this released water have on the reservoir?

Low dissolved oxygen, altered food web and decreased fish population.

Describe the global distribution of coal supplies?

Mainly in the US, Russia (Soviet Union) or china.

What country has the largest oil reserves?

Middle East (Saudi Arabia).

Which panel system is least effective at producing energy?

No tracking, tilted east

The graphs below show the energy output of one kilowatt of photovoltaic capacity of different panel systems over a day (graph on the left) and the annual energy production (graph on the right) of the same systems. Dual-axis tracking means that the panels are constantly moving to always face the Sun directly. If the panels are tilted in a fixed position, the direction of tilt is indicated. Flat panels are not tilted in any direction. 1. If peak electricity use occurs around 2 pm in the Los Angeles area and avoiding brownouts is more important to the installers of the panels than annual energy output, what orientation of panel systems would be best to use in the area?

No tracking, tilted west

Which current proven global reserves are expected to be largely exhausted within the next 50 years?

Oil

Economic benefits of building large dams include which of the following? I. Storage of water for agriculture and domestic use. II. Controlling floods upstream. III. Production of renewable energy

One and Three

There are various stages in the formation of coal as heat and pressure are increased and moisture content is decreased. These stages, in order, are what?

Peat, Lugnite, sub-bituminous, bituminous, anthracite.

Purity is a major factor in determining the type of coal used for energy. List the types of coal correctly with a description of its purity and common use.

Peat- lowest quality Lignite- second lowest quality Bituminous- second highest quality Anthracite- highest grade coal, used for domestic heating

Describe how electricity is generated using photovoltaic cells.

Photons of light excite electrons that result in a flow of current.

What environmental problems are most often associated with nuclear power?

Radioactive waste and produces thermal pollution

What actions would reduce global greenhouse emissions?

Replacing coal-burning power plants with wind farms.

Describe a way for the government to encourage efficient energy use.

Requiring higher fuel economy standards for new cars

Which region has been the largest petroleum exporter for the past four decades?

Saudi Arabia

Why are some energy sources renewable and others are not?

Some energy sources can be replenished at the rate it is used

In contrast to low-level radioactive waste, most high-level radioactive waste is currently stored where?

Stored at reactor center

What is the role of fossil fuels in the production of energy?

The combustion of fossil fuels heats water to produce steam, which ten turns a turbine Burn coal and oil the create heat

Describe how the use of hydrogen fuel negatively impacts the environment.

The energy needed to produce the hydrogen fuel may come from fossil fuels, whose use contributes to ocean acidification and global climate change.

What is a negative consequence associated with photovoltaic solar cells?

The manufacture of photovoltaic solar cells involves toxic metals that can be released into the environment.

Where does the world's energy come from?

The most widely used sources of energy globally are fossil fuels.

Given that 1 kWh = 3.6 MJ and that 1 Btu = 1055 J, show that 1 kWh = 3412 Btu. Why would it be incorrect to use this conversion factor directly to determine the amount of coal required to generate electricity in a power plant?

The second law of thermodynamics prevents 100 percent conversion of heat to mechanical or electrical energy. A typical coal-fired power plant operates at about 33 percent efficiency, meaning that only one-third of the energy in the coal is converted to electricity.

Describe the method of vehicle transport that is the most environmentally sustainable.

The use of a vehicle that is powered by hydrogen fuel cells.

What is a drawback to using biofuels, such as ethanol, as a fuel source?

There is high energy investment in producing and harvesting the crops in ethanol production.

Compared to a coal-fired power plant that produces the same amount of energy, a nuclear power plant generates more what?

Thermal pollution

What is a characteristic of nonrenewable energy sources that distinguishes them from renewable energy sources?

They exist in a fixed amount and cannot be easily replaced

Describe a benefit of increasing the number of offshore wind farms rather than onshore wind farms.

They produce three times as much electricity as wind farms on land because of increased wind speeds offshore.

Accurately describe a fuel cell vehicle.

They use hydrogen to generate electricity that runs the motor.

Define renewable energy.

Those that can be replenished naturally, at or near the rate of consumption and reused. Renewable energy sources use advanced technologies Wind, solar, hydro, tidal, geothermal, biomass

What is nonrenewable energy?

Those that exist in a fixed amount and involve energy transformation that cannot be easily replaced. Coal, petroleum oil, natural gas, nuclear energy,

What is the most practical solution to maximizing energy production at wind farms while minimizing the risk to wildlife?

Turn off turbines during periods of maximum migration.

List the top 3 countries that have the largest coal reserves?

US, Russia, china

What country has the largest coal reserves?

USA, then Russia.

Geothermal energy plants are a viable alternative energy source. Why?

Use the heat stored in the Earth's interior to heat up water, which is brought back to the surface as steam. The steam is used to drive an electric generator.

What is a disadvantage of using nuclear energy as a source of electricity?

Waste is radioactive and disposal is difficult and expensive. Local thermal pollution from the release of waste water can harm aquatic life. Spent fuel rods must be disposed of properly. Uranium-235 Remains radioactive for a long time, which leads to the problems associated with the disposal of nuclear waste

Where in the US has a history of coal deposits and is most likely to have mining operations?

West Virginia, Pennsylvania and Kentucky

Why do hybrid electric vehicles use less fossil fuel per mile traveled than atypical internal combustion engine vehicle uses?

When the brakes are applied in hybrid electric vehicles, kinetic energy is converted into electric energy to charge the batteries that assist the electric motor.

In the majority of less developed countries, the major source of energy for domestic use is what?

biomass

What gas is released from the exhaust of a nuclear power plant?

steam?

What is a major limitation of using photovoltaic cells to generate electricity? I

t's based on the availability of sunlight. If there's clouds, there wouldn't be a lot of electricity.

As the world becomes more industrialized,

the demand for energy increases.

Where in the nuclear power plant did the accidents at Three Mile Island and Chernobyl occur?

the rods inside The reactor

What is used as a fuel source for electricity generation in a nuclear power station?

uranium-235

What fuel source is commonly used in less developed countries because it is easily accessible?

wood