Sustainability in Action Study Guide Key PDF

Summary

This study guide covers topics like the composition of the atmosphere, the concept of the tragedy of the commons, and the impact of mining on the environment. It also includes questions and further information on ecological footprints.

Full Transcript

Describe the structure and composition of the Earth’s atmosphere * Earth’s atmosphere is made up of major gases that vary in concentration. * The layers of the atmosphere are based on temperature gradients and are Troposphere, Stratosphere, Mesosphere, Thermosphere, & Exosphere. 🡪 The...

Describe the structure and composition of the Earth’s atmosphere * Earth’s atmosphere is made up of major gases that vary in concentration. * The layers of the atmosphere are based on temperature gradients and are Troposphere, Stratosphere, Mesosphere, Thermosphere, & Exosphere. 🡪 The lower part of the troposphere is warmer than the upper part because the Earth absorbs sunlight and heats it. 1. What’s the first and second most abundant gas in the atmosphere? Nitrogen is 78% and Oxygen is 21% * Study your atmospheric science diagram notes! 2. What are the features of the troposphere, stratosphere, mesosphere, thermosphere, and exosphere? Troposphere – lowest layer. Where weather and greenhouse gases occur. Stratosphere – 2nd layer from the Earth. Contains the ozone layer Mesosphere – 3rd layer from the Earth. Thermosphere – 4th from the Earth. Where aurora borealis occurs. Exosphere – border of atmosphere. 5.1 Explain the concept of the tragedy of the commons * The tragedy of the commons suggests that individuals will use shared resources in their own self-interest rather than in keeping with the common good, thereby depleting the resource. More to know and understand: 1. What are some examples of commons? Shared resources such as public lakes (not private), national forests (not all forests), the ocean, air, drinking water that’s managed as a commons (vs. water rights), city parks, public libraries, public schools, national, state and and county parks, etc. 2. What are solutions to tragedy of the commons? Quotas, limits, size limits (such as for fish), only catch males (such as for fish), fines, laws, fees, licenses. 5. 9 Describe how natural resources are obtained through mining, and the ecological and economic impacts of mining Basic Information about Surface Coal Mining in Appalachia | US EPA Basic Information about Surface Coal Mining in Appalachia | US EPA Images EPA * As the more accessible ores (minerals mixed with impurities) are mined to depletion, mining operations are forced to access lower grade ores (not as pure). Accessing these ores requires increased use of resources that can cause increased waste and pollution. 1. What types of resources are used in mining? Fossil fuels for machinery, water, land * Surface mining is the removal of large portions of soil and rock, called overburden, in order to access the ore underneath. An example is strip mining, which removes the vegetation from an area, making the area more susceptible to erosion. 2. Why does this increase erosion? When vegetation is removed, there aren’t roots to hold soil in place and erosion increases. * Mining wastes include the soil and rocks that are moved to gain access to the ore, and the waste (slag/tailings) that remain when the minerals have been removed from the ore. Mining helps provide low-cost energy and material necessary to make products. The mining of coal can destroy habitats, contaminate groundwater, and release dust particles and methane. 3. What is acid mine drainage? During mining, acidic rock is exposed. Precipitation erodes the acidic rock into surface water. * As coal reserves get smaller, due to a lack of easily accessible reserves, it becomes necessary to access coal through subsurface mining, which is very expensive and dangerous. More to know and understand: 4. What are some human health problems with mining? Black lung disease from coal mining, accidents, drinking water contamination 5. How does mining lead to habitat fragmentation? Surface mining destroys habitat in pieces throughout an ecosystem. For example, mountaintop removal destroyed habitat on the peaks of several mountains in a range. 6. What is mountaintop removal? The removal of the peak of a mountain for coal – typically in the Appalachian Mountains. Reclamation is impossible. 7. What is reclamation? Restoring the habitat of an area after mining is finished. It is the law in the United States for many locations and types of mining, but not everywhere or for all types of mining. 8. Why is reclamation difficult in some locations? Replacing the top of a mountain is impossible. In other locations, topsoil has been decimated so re-planted areas do not grow. 9. Why is surface coal mining less expensive than subsurface mining? Surface mining is less dangerous for miners and therefore less accidents, medical costs and lawsuits. 10. How does mining lead to water pollution? Which pollutants? Some types of mining expose acidic rock and sulfur which causes acid-mine drainage. Gold mining uses cyanide which can spill into surface water and kill marine life. 5.11 Explain the variables measured in an ecological footprint * Ecological footprints compare resource demands and waste production required for an individual or a society. * Measured in AREA of LAND! More to know and understand: 1. What kinds of lifestyle choices go into an ecological footprint calculation? Goods and services, food, carbon emission, housing, energy, and transportation. 2. What type of countries have the largest ecological footprints? Developed countries. 3. What are limitations of ecological footprint calculators? They cannot possibly measure everything environmental impact of an individual. 6.1 Identify differences between nonrenewable and renewable energy sources Know: * Nonrenewable energy sources are those that exist in a fixed amount and involve energy transformation that cannot be easily replaced. * Renewable energy sources are those that can be replenished naturally, at or near the rate of consumption, and reused. More to know and understand: 1. What are some examples of nonrenewable resources? Coal, petroleum (oil), natural gas, minerals, gems, metals, uranium (for nuclear power) 2. What are some examples of renewable resources? Solar, wind, geothermal, water and hydropower, tidal, wave, biomass (crops, wood, algae, and other plants), geothermal energy. 3. Can you describe something as renewable if it is reusable or recyclable? Why or why not? No, because non-renewable resources such as metals can be re-used and recycled. 4. Can renewable resources run out temporarily? Explain Yes, water can run out during a drought, forests can be depleted until they grow back, geothermal power can decrease if groundwater is depleted faster than replenished through the water cycle. ________________________________________________________________________________________________ 6.2 Describe trends in energy consumption Know: * The use of energy resources is not evenly distributed between developed and developing countries. * The most widely used sources of energy globally are fossil fuels * As developing countries become more developed, their reliance on fossil fuels for energy increases. * As the world becomes more industrialized, the demand for energy increases. * Availability, price, and governmental regulations influence which energy sources people use and how they can use them. More to know and understand: 1. What are BTUs, Watts, Therms and Joules and how are they used in calculating energy? Note: You do not need to memorize exact definitions nor conversions between them. Ways that we measure energy. BTUs and joules are often used for general energy production, watts are used with electricity generation and use, and therms for natural gas bills. Make sure you know these metric conversions with watts. You will NOT need to convert between energy units such as Joules to Watts. 2. How many Watts in a Kilowatt? 1000 3. How many Watts in a Megawatt? 1,000,000 4. How many Kilowatts in a Megawatt? 1000 Chart, pie chart Description automatically generated 5. Math Practice: Use the pie graph to calculate: If the US uses 99 quadrillion BTUs of energy each year, how many BTUs for transportation? 99 quadrillion BTU X.28 = 27.72 BTU 6. Math Practice: If the US uses 99 quadrillion BTUs of energy in 2022, and are projected to use 143 quadrillion BTUs by 2050, what is the percent increase? (143 quadrillion BTU - 99 quadrillion BTU)/ 99 quadrillion BTU X 100 = 44% increase __________________________________________________________________________________ 6.3 Identify types of fuels and their uses Know: * Wood is commonly used as fuel in the forms of firewood and charcoal. It is used in developing countries because it is easily accessible. * Peat is partially decomposed organic material that can be burned for fuel. * Natural gas, the cleanest of the fossil fuels, is mostly methane * Crude oil can be recovered from tar sands, which are a combination of clay, sand, water, and bitumen. * Fossil fuels can be made into specific fuel types for specialized uses (ie, aviation fuel, motor vehicle fuel). * Cogeneration occurs when a fuel source is used to generate both useful heat and electricity. More to know and understand: 🡪 The fossil fuel “oil” can also be called petroleum and crude oil. We can pump crude oil from the ground, mine petroleum from tar sands and extract petroleum from shale using fracking. 1. What is peat a precursor to? Under what conditions is it made? Partially decayed vegetation is placed under high-pressure, anaerobic, acidic conditions. 2. What are the main grades of coal? Which has the highest level of carbon? Which is the best in terms of energy per volume? Which type of coal has the highest sulfur content? Anthracite (highest energy per volume), bituminous (most sulfur content) and lignite (lowest energy per volume) 3. What is an example of cogeneration? In an apartment building, exhaust from a gas-powered electrical generator is captured to produce hot water to heat a swimming pool. 4. Why has coal in powerplants declined while natural gas has increased? Coal has more air pollution and releases more carbon than natural gas which is why its phased out in favor of natural gas. In addition, the increase in fracking has increased the amount of available natural gas. 5. Which fuel causes deforestation? Biomass to use trees for heating or cooking or to grow crops for energy. 6. Which fossil fuel is the most consumed in the world for total energy? (and also most consumed for commercial energy) Petroleum/Crude Oil 7. Which fossil fuel is the most consumed for electricity? Coal, but being replaced by natural gas ________________________________________________________________________________________________ 6.4 Identify where natural energy resources occur Know: * The global distribution of natural energy resources, such as ores, coal, crude oil, and gas, is not uniform and depends on the region's geologic history. More to know and understand: 🡪Petroleum and natural gas are mainly ancient plankton in ancient oceans. Coal is ancient swamp trees. Review coal mining and its impacts from Unit 5. 1. How is oil trapped underground? How does porosity and permeability of rock and soil layers trap oil? Erosion and plate tectonics move the crust to trap dead organic matter. Heat and pressure and millions of years transforms organic matter into fossil fuels. An impermeable rock can trap oil underground. Porous rock can hold oil and natural gas. 2. Which energy sources are not derived directly nor indirectly from the sun? Geothermal and Nuclear energy. 3. Where are the main coal deposits in the United States? Appalachian mountains and Montana ______________________________________________________________________________________ 6.5 Describe the use and methods of fossil fuels in power generation and the impact they have on the environment. Know: * Combustion of fossil fuels is a chemical reaction between the fuel and oxygen that yields carbon dioxide, water, and released energy. * Energy from fossil fuels is produced by burning those fuels to generate heat, which then turns water into steam. That steam turns a turbine, attached to a generator, which converts the mechanical energy into electrical energy. * Humans use a variety of methods to extract fossil fuels from the earth for energy generation (oil drilling (land and offshore), fracking, etc.) * Fracking can cause groundwater contamination and the release of VOC’s. Delivery to consumers - U.S. Energy Information Administration (EIA) More to know and understand: In a coal/natural gas/nuclear power plant, energy is converted from thermal energy (combustion or nuclear fission)🡪 kinetic energy 🡪 mechanical energy (turbines) 🡪 electrical energy (generator) 🡪 Know how electricity is generated and the parts of power plant from your energy diagram packet. (Delete this if you are not using the packet) 1. Which is the cleanest fossil fuel to burn? Natural Gas 2. What greenhouse gasses are emitted from burning fossil fuels? Carbon (which turns into carbon dioxide in the air, NOx, Methane 3. Which fossil fuels primarily is used in transportation? Petroleum/Oil 4. How is oil extracted with and without fracking? Without fracking, a well is dug past impermeable rock to release trapped oil and natural gas. If oil/natural gas is trapped in porous rock, water or chemicals are forced underground to crack the rocks and release the oil and gas. 5. What fuel is often next to crude oil and can be harvested as well? Natural Gas 6. What is bitumen? Where do we extract from? A form of petroleum extracted from tar sands. Very thick with more air pollutants 7. What is keratin? Where do we extract from? A form of petroleum found in shale. Must be fracked to access. 8. What are the risks with offshore drilling for oil? Accidents and spills which injure marine life. 9. What are the main problems with drilling for oil on land? Fracking can damage groundwater supplies for drinking and agriculture. Wells and pipes can spill and damage habitat. 10. How does fracking work? If oil/natural gas is trapped in porous rock, water or chemicals are forced underground to crack the rocks and release the oil and gas 11. What are the environmental impacts of fracking? Natural gas and the chemicals used in fracking can leak into aquifers which are used for drinking and agriculture. Increase in earthquakes. 6.13 Describe methods for conserving energy Know: * Some of the methods for conserving energy around a home include adjusting the thermostat to reduce the use of heat/AC, conserving water, use of energy-efficient appliances, and conservation landscaping. * Methods of conserving energy on a large scale include improving fuel economy for vehicles, using BEF’s (battery electric vehicles) and hybrid vehicles, using public transportation, and implementing green building design features. More to know and understand: 1. Why aren’t PV cells considered energy conservation? PV cells (solar panels) do not conserve (reduce) energy use -it just switches to a renewable form. 2. What are CAFE standards? Why are they helpful? Corporate Auto Fleet Efficiency – the maximum average mpg of the vehicles a car company sells. It pushes manufacturers to produce more efficient vehicles. 3. What are subsidies? Government payments (via tax money) to help offset the cost of doing business. Makes prices cheaper for consumers. 4. What are tax breaks? A reduction of taxes for things such as purchasing an electric car. 5. What are some features of green building design that helps with energy conservation? Green roof, LED lights, insulation, double-paned windows, landscaping, smart thermostat. 7.1 Identify the sources and effects of air pollutants Know * Coal combustion releases air pollutants including CO, CO2, SO2, toxic metals and particulates. * The combustion of fossil fuels releases nitrogen oxides (NOx) into the atmosphere. They lead to the production of ozone, formation of photochemical smog, and convert to nitric acid in the atmosphere. Causing acid rain. Other pollutants produced by fossil fuel combustion include CO, hydrocarbons, and particulate matter. * Air quality can be affected through the release of SO2 during the burning of fossil fuels, mainly diesel fuels. * Through the Clean Air Act, the Environmental Protection Agency (EPA) regulated the use of lead, particularly in fuels, which dramatically decreased the amount of lead in the atmosphere. * Air pollutants can be primary or secondary pollutants. Overview of the Clean Air Act and Air Pollution | US EPA Photo credit: EPA Open Source More to know and understand: 1. Define primary air pollutant: Comes directly from the emission point such as a smokestack or a tailpipe. 2. Define secondary air pollutant: A primary pollutant that mixes with another pollutant or an atmosphere gas to form a new pollutant. 3. What pollutants are primary? CO, NOx, SO2, PM, VOCs, Lead, toxic metals, hydrocarbons 4. What pollutants are secondary? NOx, PM, VOCs (all can be both primary and secondary), Tropospheric Ozone, CO2, Acid rain molecules (Sulfuric acid (H2SO4), nitric acid (HNO3). 5. How does lead impact human health? Causes neurological damage, lowers IQ, Organ damage 6. What was done to decrease the amount of airborne lead? Mandated unleaded gasoline several decades ago. 7. Where does airborne mercury come from? Burning coal. 8. What are airborne hydrocarbons? An organic chemical compound that is composed exclusively of hydrogen and carbon atoms. Produced through burning fossil fuels. 9. What are the main health effects of air pollution? (Hint, it’s not lung cancer). Respiratory problems such as asthma, emphysema etc. 10. What are the main provisions of the Clean Air Act? The act establishes federal standards for mobile sources of air pollution and their fuels and for sources of air pollutants, and it establishes a cap-and-trade program for the emissions that cause acid rain. It establishes a comprehensive permit system for all major sources of air pollution. _____________________________________________________________________________________________________ 7.2 Explain the causes and effects of photochemical smog and methods to reduce it Know: * Photochemical smog is formed when NOx and VOCs react with heat and sunlight to produce a variety of pollutants. * Many environmental factors affect the formation of photochemical smog. * NOx is produced early in the day. Ozone concentrations peak in the afternoon and are higher in the summer because ozone is produced by chemical reactions between oxygen & sunlight. * Volatile Organic Compounds (VOC’s) such as formaldehyde and gasoline, evaporate or sublimate at room temperature. Trees are a natural source of VOCs. * Photochemical smog often forms in urban areas because of the large number of motor vehicles there. * Photochemical smog can be reduced through the reduction of NOx and VOCs. * Photochemical smog can harm human health in several ways, including causing respiratory problems and eye irritation. Ground-level Ozone Basics | US EPA How BenMAP-CE Estimates the Health and Economic Effects of Air Pollution | US EPA Photo credits: EPA Open source More to know and understand: 1. In which season is tropospheric ozone higher? Why? Summer, because there is more LIGHT (not heat) from the sun to cause NOx to react and form ozone. 2. Where does NOx come from? Why is NOx produced early in the day? Burning fossil fuels – primarily petroleum (gasoline, diesel, and jet fuel). Produced from morning rush-hour traffic/commutes to work. 3. Why does ozone peak in the afternoon? By afternoon, NOx has had a lot of time in sunlight to transform into ozone. 4. Which locations in a city would have higher ozone? Near a major highway/road/freeway, or airport or port. 5. Name some examples of VOCs. Gasoline vapor, benzene, formaldehyde, smelly trees and plants, solvants, paint, many fragrances. 6. How do VOCs worsen the formation of tropospheric ozone? Under sunlight, VOCs react with nitrogen oxides to form ozone. They stop the cycle of NOx and ozone forming and breaking apart so ozone builds up. ____________________________________________________________________________________ 7.3 Describe thermal inversion and its relationship to pollution Know: * During a thermal inversion, the normal temperature gradient in the atmosphere is altered as the air temperature at the Earth’s surface is cooler than the air at higher altitudes. * Thermal inversion traps pollution close to the ground, especially smog and particulates. More to know and understand: 7. Describe the normal troposphere in terms of air temperature and altitude. Warming temperatures near the surface of the Earth and gradually cooling as you go higher in the atmosphere. 8. Describe a thermal inversion in terms of air temperature and altitude. A layer of cool air gets trapped near the surface of the Earth with warmer air above it. 9. How do thermal inversions form in coastal areas? Cool, coastal breezes blow onto land cooling the air near the surface of the Earth. 10. How do thermal inversions form in valleys? In the late afternoon, the sun dips below the tops of high mountains casting a shadow on the valley floor which slightly cools that area, but the air above it is warmer. 11. What prevents air masses from mixing during thermal inversion? Different temperatures have different densities which do not mix. ______________________________________________________________________________________________________ 7.4 Describe natural sources of CO2 and particulates Know: * CO2 appears naturally in the atmosphere from sources such as respiration, decomposition, and volcanic eruptions. * There are a variety of natural sources of particulate matter (PM). More to know and understand: 12. What are geologic sources of CO2? Volcanoes, geothermal gases, forest fires, erosion of rocks containing carbon. 13. What are biologic sources of CO2? Decomposition, cellular respiration (but it doesn’t increase overall atmospheric carbon dioxide, because photosynthesis offset it). 14. How do we measure CO2 in the atmosphere? What units? Direct measurements in ppm. We can determine levels of CO2 from the past through ice cores. 15. What is the Mauna Loa Observatory and the Keeling curve? The Mauna Loa Observatory is in Hawaii and is one of the locations we measure atmospheric CO2. Charles Keeling started doing this in 1956 and it is an active and current measurement. You can find the current level here https://keelingcurve.ucsd.edu/ 16. What are some natural sources of PM? Volcanic eruptions, dust, pollen, natural wildfires, sea salt. 17. What are anthropogenic sources of PM? Anthropogenic wildfires, construction (dust), burning fossil fuels, tilling the soil, dusty roads. 18. What does PM10, PM2.5 and PM0.1 mean? Which is worse for health? Why? The number after PM is for the length in microns. PM0.1 is the worst, because it is so small and evades the body’s natural defenses in the respiratory system and can enter the blood stream. _____________________________________________________________________________________________________ 7.5 Identify indoor air pollutants and their effects Know: * CO is an indoor air pollutant that is classified as an asphyxiant. * Indoor air pollutants that are classified as particulates include asbestos, dust, and smoke. * Indoor air pollutants can come from natural sources, anthropogenic sources, and combustion. * Common natural sources indoor air pollutants include radon, mold, and dust. * Common anthropogenic indoor air pollutants include insulation, VOCs from furniture, paneling, and carpets, formaldehyde from building materials, furniture, upholstery, carpeting, and lead from paints. * Common combustion air pollutants include CO, NOx, SO2, particulates, and tobacco smoke. * Radon-222 is a naturally occurring radioactive gas that is produced by the decay of uranium found in some rocks and soils. * Radon gas can infiltrate homes as it moves up through the soil and enters homes via the basement or cracks in walls or foundations. It is also dissolved in groundwater that enters homes through a well. * Exposure to radon gas can lead to radon-induced lung cancer, which is the second leading cause of lung cancer in America. More to know and understand: 19. What is an asphyxiant? A gas that reduces or displaces the normal oxygen concentration. 20. Where does asbestos come from? What are its health effects? Old insulation. Causes mesothelioma (lung cancer) and other respiratory problems. 21. Where does mold come from in a home? What are its health effects? Damp areas. Causes respiratory problems, allergies, infections, and autoimmune problems. 22. Where is radon usually found in homes? What are its health effects? Basement, because it seeps in from the bedrock. Causes lung cancer, 23. What are some ways to mitigate radon? Vent systems. 24. What are some ways to mitigate or prevent other indoor air pollutants? Open windows when outdoor air pollution is minimal, don’t use wood fireplaces, use VOC-free paint, use unscented products. Air filters. 25. What is the number one cause of death from indoor air pollution in developed countries? In developing countries? Developed countries is cigarette smoke. Developing countries: Indoor cooking fires. 26. How can people in developing countries reduce indoor cooking fires from biomass? Good ventilation, solar ovens. ____________________________________________________________________________________________ 7.6 Explain how air pollutants can be reduced at the source Know: * Methods to reduce air pollutants include regulatory practices, conservation practices, and alternative fuels. * A vapor recovery nozzle is an air pollution control device on a gasoline pump that prevents fumes from escaping into the atmosphere when fueling a vehicle. * A catalytic converter is an air pollution control device for internal combustion engines that convert pollutants (CO, NOx, hydrocarbons) in exhaust into less harmful molecules (CO2, N2, O2, and H2O). * Wet and dry scrubbers are air pollution control devices that remove particulates and/or gases from industrial exhaust streams. * Methods to reduce air pollution from coal-burning power plants include scrubbers and electrostatic precipitators. A picture containing diagram Description automatically generated Electrostatic Precipitator and Wet Scrubber. Picture Credits: EPA Monitoring by Control Technique - Wet Scrubber For Particulate Matter | US EPA More to know and understand: 27. What is the difference between a wet and dry scrubber? A wet scrubber reduces SO2 and uses chemical reactions. A dry scrubber uses fabric filters to capture particles. 28. What does an electrostatic precipitator do? Reduces particulate matter. 29. Which air pollutant has declined 99% due to its elimination from gasoline? Lead 30. Describe the following and how it reduces photochemical smog: 1. Catalytic converter On cars, it converts hydrocarbons, CO and NOx to less-toxic pollutants. 2. Smog check In some states, cars are required to test their emissions and have limits. 3. Vapor recovery nozzle In some states, gas pumps have nozzles that prevent VOCs from escaping. 4. Emission standards The Clean Air Act limits the number of pollutants in the air and that can also be emitted from point sources. Some states (such as CA) have stricter emission standards to reduce the vast amount of air pollution. ______________________________________________________________________________________________ 7.7 Describe acid deposition and its environmental impacts Timeline Description automatically generated Picture Credit: EPA 🡪Note where clean rain and acid rain are on the pH scale above. Know: * Acid deposition is due to NOx and SO2 from anthropogenic and natural sources in the atmosphere. * NOx that causes acid deposition come from vehicles and coal-burning powerplants. SO2 that causes acid deposition comes from coal-burning power plants. * Acid deposition mainly affects communities that are downwind from coal-burning power plants. * Acid rain and deposition can lead to the acidification of soils and bodies of water and corrosion of man-made structures. * Regional differences in soils and bedrock affect the impact that acid deposition has on the region- such as limestone bedrock’s ability to neutralize the effect of acid rain on lakes/ponds. Diagram Description automatically generated More to know and understand: 31. What are natural sources of acid deposition? Volcanic eruptions and decomposition 32. What are anthropogenic sources of acid deposition? Burning fossil fuels 33. What are the equations that form sulfuric acid and nitric acid? 2SO2 – O2 🡪 2SO3, then SO3 + H2O 🡪 H2SO4. (Sulfuric acid) 2NO2 + H2O 🡪 HNO3 + HNO2 (Nitric acid and Nitrous acid) 34. What human structures are degraded from acid deposition? Tombstones, statues, marble buildings 35. How does it impact soils? Discuss aluminum and calcium ions and nutrient uptake. Causes aluminum to rise in the soil which is toxic ot fish and plants. It also dissolves calcium which plants need. 36. How does it impact forests? Aluminum released in soil makes it difficult for trees to take up water. 37. How does it impact the productivity of marine organisms? Aluminum can leach from soils into water and is toxic which will lower productivity. Acid rain can also cause phytoplankton in lakes to die. 38. How does it impact bodies of water? Lowers the pH which is out of the range of tolerance for many species. 39. How does calcium carbonate (limestone) help to buffer soil or water? What else can buffer? calcium carbonate acts to neutralise or buffer the solution by consuming hydrogen ions

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