Energy

Question 1

Explain the importance of renewable energy

Answer 1

There is over 80% of the global energy which is derived from fossil fuels not even 10% is derived from renewable energy sources. Renewable energy sources are important because they do not exceed any emissions, namely, wind power and solar power. Biofuel emits significantly less than fossil fuels. The only catch fossil fuels are required for bio crops, biofuels and wind turbines. Carbon dioxide methane and nitrous oxides are all produced in extraction of fossil fuels.

Question 2

Whats the deal with aerobic and photosynthesis

Answer 2

Aerobic respiration and photosynthesis play a vital role in the maintenance of the cycling of carbon dioxide and oxygen in the Earth. The carbon dioxide is cycled. Photosynthesis involves carbon dioxide and water to store energy in the form of glucose is a very highly complex process. Moreover, the glucose is liberated in the exothermic reaction of aerobic respiration using the glucose to form energy. The basis of photosynthesis and aerobic respiration form a basis in the carbon cycling on Earth supporting food webs and food chains. Light energy is absorbed by the chlorophyll.

Question 3

Whats the deal with fossil fuels

Answer 3

Fossil fuels; coal, petroleum and natural gas are formed naturally from anaerobic decomposition. They are referred to as non-renewable energy as they are depleted faster than they are formed. Moreover, the petroleum is found naturally in the sedimentary rock deposits. Petroleum is formed from anerobic decomposition in the earth’s surface and from the high pressures in the Earth crust. Petroleum is a complex mixture of 30% alkane, 50% naphthalene, 15% aromatics and 5% asphaltenes. Petroleum is found anerobic decomposition of plankton and algae.

Question 4

What is natural gas

Answer 4

Natural gas is a natural mixture that is formed by the anaerobic decomposition of animals and plants under high pressures and temperature. The natural gas is found in sedimentary rocks the deposits. Moreover, natural gas is formed from complex carbon compounds such as methane 90% methane 5% ethane propane 3% and 2% was other larger hydrocarbons.

Question 5

What is coal

Answer 5

Coal is a heterogenous mixture composed of carbon (organic) compounds along with hydrogen, sulphur and nitrogen. Coal is formed from the anerobic decomposition of organic compounds, namely, plants over millions of years. Moreover, it has a carbon concentration of over 50% w/v and there is trace amounts of over 70 elements and oxides found in it from atomic spectroscopy.

Coal is found deep within the Earth’s crust and found and surface it used for fuel source. It has two principal purposes fuel source and feedstock to manufacture for other materials. And fuel for storing chemical energy and extracting to perform mechanical tasks.

Question 6

Fossil fuels uses

Answer 6

Fossil fuels are the primary source of energy accounting for 80% of global consumption. Coal, natural gas and petroleum contain compounds which are high combustion-able with the presence of an appropriate oxidiser (usually O2). Combustion releases heat and electricity which can be used by sectors including industry roughly 53% transport 26%, residential homes 14% and commercial business 8%

Question 7

Advantages of fossil fuels

Answer 7

Advantages
Currently fossil fuels are abundant and accessible
Fossil fuels have high energy density and large quantities of energy are released in the combustion of these materials
Extraction of fossil fuels is relatively easy and inexpensive
Fossil fuels are feedstock for thousands of commercially available products that are used in everyday living

Question 8

Disadvantages of fossil fuels

Answer 8

Carbon dioxide (greenhouse gas) is released in the combustion of fossil fuels
Sulphur oxides (SOx) and nitrogen oxides (NOx) are released when coal and oil undergo combustion. These gases contribute to acid rain and smog.
Particular matter (PM) is released into the atmosphere in the extraction of coal and these materials are major contributors to global air pollution
Fossil fuels are non-renewable and cannot be replaced once they are consumed.

Question 9

Fossil fuel feedstocks

Answer 9

Petroleum comprises most of the feedstock for fossil fuels 20% of all petroleum extraction is used for feed stock annually with over 5000 consumer goods. Including, alkenes as manufacture of polymers larger alkenes as lubricants, asphalt for road production and aromatic compounds as manufacture of polymers/solvents. Natural gas is also used as a feedstock for nitrogen fertilisers, hydrogen gas and methanol.

Question 10

Advantages of wind power

Answer 10

Wind is an inexhaustible recourse of renewable energy with zero emissions of greenhouse gases during operation.
Currently wind power is one of the most cost-effective renewable energy technologies
Wind turbines do not require the use of water whereas steam turbines (used in power stations where fossil fuels are combusted) require large amounts of water.

Question 11

Disadvantages of wind power

Answer 11

Wind turbines cannot provide a sustainable source of energy for domestic use in the absence of wind (can be unreliable.)
The best locations for wind turbines are often great distances from the users of electricity meaning that the power transmitted (inefficiently) over long distances
Wind turbines create noise pollution, have been describes as unsightly, and have been implicated in the death of birds and bats.

Question 12

Whats the deal with wind power

Answer 12

Kinetic energy is converted to electrical energy by wind turbines. The large blades capture wind energy and turn it to electrical energy. The wind turbines are grouped together to form wind farms that are collectively used to form generate electricity for homes and businesses. Currently there are 16 wind farms in Australia.

Question 13

Biofuel generations

Answer 13

Generation Description Examples

First Produced directly from food crops Bioethanol, biodiesel

Second Product from non-food crops such as wood, food crop waste, and organic waste Biogas (50-80% methane)

Third Produced in chemical processes carried out by genetically engineered algae. Biodiesel, butanol, gasoline, methane, and bioethanol

Question 14

Whats the deal with Bioethanol

Answer 14

Bioethanol is produced from the biochemical reaction called anaerobic fermentation. It involves a microorganism (fungi) called yeast as it has an enzyme called zymase which catalyses the reaction for anaerobic reaction. Plant matter is used for it including, wheat, sugar cane, it involves the catalysation to create ethanol bioethanol. It is then able to be mixed with gasoline. Gasoline causes greater CO2 emissions per mole than biofuels. Gasoline is comprised mainly from fossil fuels. The reaction must be aqueous, be between 6.1 to 6.8 pH. 25 to 35 degrees anaerobic environment in case of oxygen which causes ethanoic acid.

Question 15

Advantages of biofuel

Answer 15

Advantages
Combustion of biofuels produces fewer greenhouse gases.
Biofuels crops remove carbon dioxide from the atmosphere during photosynthesis
Waste material can be used to produce biofuels which reduce emissions of greenhouse gases from waste and landfill.
Biofuel crops can be grown every year creating a renewable fuel source which has greater security in the future.

Question 16

Disadvantages of biofuel

Answer 16

Disadvantages
Greenhouse gases are emitted in the fertilising, harvesting, refining and transporting of biofuel crops.
Biofuel crops occupy land that could be used for growing crops. This could lead to higher food prices in future.
The growth of biofuel crops requires a large amount of water which will contribute to water shortages in future.
The demand for palm oil has caused deforestation in some areas of the world.

Question 17

Outline what biofuels are.

Answer 17

Biofuels are derived from living or recently living matter from plants and animals and waste products. Bioethanol or biodiesel are biofuels. They are used to reduce the global demand of petroleum as a fuel source. Moreover, bioethanol is found derived from anerobic fermentation glucose (plant matter). Biodiesel is from plant oils.

Question 18

Advantages of solar cells

Answer 18

Solar cells require very little maintenance once installed properly.
Solar cells can be engineered to any size to suit a variety of applications from charging a phone to powering a building.
The sun provides an inexhaustible amount of renewable energy that can be converted into electrical energy in all parts of the planet.
Conversion of electromagnetic radiation (light) into electric current does not involve any greenhouse gas emissions.

Question 19

Disadvantages of solar cells

Answer 19

Power output of solar cells decrease in the absence of sunlight (at night) and in periods of high cloud cover
Solar cells in solar panels are fixed in a position that is not always facing the sun.
Currently solar cells have low energy efficiency (~20%) but advances in nanoscience and technology are improving the efficiency of solar cells every year.
80% of solar cells are made from high purity silicon which is an expensive raw material which greatly reduces the cost-effectiveness of solar cells.

Question 20

Whats the deal with solar power

Answer 20

Solar power is generated from electromagnetic radiation from the sun. Solar power is used to reduce the dependence of fossil fuels for energy production. Essentially, photovoltaic cells are found on rooves and convert energy from the sun to electrical energy. The photovoltaic cells are connected together to form power stations.

Question 21

How are biodiesel made

Answer 21

Biodiesel are esters compared with fatty acids with low molar mass alcohols such as ethanol or methanol. The ester is made in a process called transesterification involving the fatty acid and the low molar mass alcohol to form the biodiesel. It can be used in its pure form or combined with another diesel to create a combination which contributes to less fuel used annually. Moreover, the biodiesel emits less carbon dioxide than regular diesel. Oil seed crops are main sources of biofuel production

Question 22

Describe complete combustion

Answer 22

Combustion involves the chemical reaction of a fuel and an oxidiser (usually oxygen.) It involves the burning of a molecule containing carbon and hydrogen with to form water, energy and carbon dioxide. The hydrocarbons are combusted in an exothermic reaction (energy released in formation in new bonds of products is greater than energy required for the break existing bonds in reactant.) Complete combustion occurs when there is enough oxygen available for carbon. To convert of carbon atoms to hydrocarbons. Energy is released in formation of new chemical bonds. In thermochemical reactions the enthalpy changes and states of matter are expressed. Moreover, the number of moles is accounted for instead of molecules. Thus, it is acceptable for there to be half moles in the coefficients in thermochemical reactions.

Question 23

Whats the deal with incomplete combustion

Answer 23

Incomplete combustion is formed when there is an incomplete amount of oxygen to convert the carbon atoms into CO2. The incomplete combustion releases low amounts of energy in comparison to the complete combustion as less bonds are formed. Tin addition, soot formed from a mixture of carbon compounds is formed and carbon monoxide.

Soot contains carbon compounds that are mutagens and cause DNA changes that cause cancer. The compounds are called polyaromatic hydrocarbons. Usually, from vehicle motors or power stations. (naphthalene, anthracene, pyrene). Soot at inhalation causes respiratory problems, cancer, birth defects and cardiovascular issues. Soot contributes to global warming in two ways through the absorbing incoming solar radiation. In addition to causing nucleation sites causing the water vapour to condense and form clouds. Cloud cover increases absorption of infrared radiation from surface. Finally, carbon monoxide displaces oxygen causing respiratory problems. With any animals with haemoglobin. Less oxygen transported to cells.

Question 24

What is the deal with calorimetry

Answer 24

Calorimetry is a technique to measure the amount of heat formed in a reaction. The larger the carbon change in a homologous series is the more energy is released per mole in a complete reaction of oxygen. Calorimetry is used to measure the energy released per mole of simple hydrocarbons and alcohols. The molar enthalpy. The bond formation of water and carbon dioxide is exothermic.

Question 25

How are measurements obtained in calorimetry

Answer 25

The mass of the known fuel combusted is to the water to measure the heat transfer. It is assumed all heat is transferred to the water. The heat transferred to the water is proportional to the water increase. Moreover, the water heat increase is proportional to the water storage capacity which is the amount of heat required for the water to increase per 1g. The water. Molar enthalpy is equal to heat released from fuel divided by number of moles combusted.

The specific energy is the amount of energy contained per unit of mass. The molar energy is the energy evolved divided by the fuel’s moles combusted in the reaction. Molar fuel is the amount of energy released when combusted. Specific energy is unit per gram. Found by molar enthalpy divided by molar.

Question 26

What is energy density

Answer 26

Energy density is the fuel contained per unit of volume. Mixtures do not usually have a molar enthalpy as they have different molecules within them. The energy density is expressed per unit of volume. Kilojoules per litre. Specific heat multiplied by fuel density.

Question 27

What is the deal with Steam turbines

Answer 27

Over 65% of global electricity is from fossil fuels globally and 85% in Australia. 73% coal 13% natural gas and 14% renewable energy. The fuel is combusted, and the combusted fuel is converted to a large water volume that uses the kinetic energy for electrical energy. The energy combusted releases carbon dioxide. It involves a boiler, steam turbine and electrical generator.

Question 28

How electricity is obtained from photovoltaic cells

Answer 28

The electrons are travelled to the semiconductor of silicon which then transfers the electrons of the excited state to form an electric current which can be used for energy. The reaction does not use any greenhouse gases. The galvanic cells use the silmountous redox reaction of the cathode and anode reactions. The flow of electrons provides energy. Electrochemical cells.

Question 29

Fuel cell makeup

Answer 29

Component Description
Flow plate Made of electrically conductive materials including metals, graphite and some polymers.
Anode (negative terminal) Porous electrode containing a precious metal (platinum) that catalyses the oxidation of fuel at the interface between the anode and electrolyte.
Cathode (positive terminal) Porous electrode containing a metal that catalyses the reduction of the oxidiser at the interface between the cathode and electrolyte.
Electrolyte A material that allows ions (not electrons) to flow as a current between the anode and cathode.

Question 30

What are the deal with fuel cells

Answer 30

Fuel cells are galvanic cells that which the reactants require a continuous supply. It differs from batteries as the products flow in and out of the cell continuously during the experiment. Electrotype allows ions to flow as a current between anode and cathode. Porous electrode containing a metal that catalyses the reduction of the oxidiser. Flow plate is made of electrically conductive materials including metals graphite and some polymers.

Question 31

Advantages of fuel cells

Answer 31

Fewer greenhouse emissions. Hydrogen fuel cells do not emit carbon dioxide in the atmosphere.

Fewer pollutants emitted. Fuel cells do not emit particular matter (PM). Nitrogen oxides (NOx) or sulphur oxides (SOx)

High energy efficiency The efficiency of a fuel cell in converting chemical to electrical energy is 40-60%

Greater power output. Fuels used in fuel cells have greater energy density than fuels used in batteries to generate electricity.

Question 32

Disadvantages of fuel cells

Answer 32

Expensive raw materials. High purity fuels and precious metal catalysts used in fuel cells are expensive.

Hydrogen is derived from fossil fuels Most hydrogen fuel is derived from the reaction of natural gas (fossil fuel) and methane

Hazards associated with some raw materials Hydrogen fuel is potentially explosive, and some electrolytes used in fuel cells are highly corrosive.

Contamination of electrolytes and electrodes Electrolytes and electrodes can be contaminated during operation by impurities in the fuel and oxidant which reduces operating efficiency.

Question 33

The application of fuel cells include.

Answer 33

• Fuel cells are used as a primary source in residential, commercial and industrial buildings.
• Fuel cells have been used as a power source in portable electronic devices and some have applications as electrochemical sensors in breathalysers and carbon monoxide detectors.
• Fuel cells have replaced the internal combustion engines in some motor vehicles.
• Fuel cell electric vehicles (FCEVs) including cars, buses, motorcycles, and boats generate energy for motion with fewer greenhouse gas emissions.

Question 34

What is the deal with flow cells.

Answer 34

Flow cells are a type of galvanic cell which reversibly converts chemical energy to electrical energy. The flow cells are used to store and discharge electrical energy. In the process, the electrical energy does not create greenhouse gas. Storage tanks store electrolytes. Anode contains reducing agent. Cathode contains oxidising agent. Ion exchange membrane allowing ions to exchange through between anode and cathode. The pumps force through the electrets through the storage tanks to electrochemical cell.