Poluentes da combustão: prever produtos e avaliar controles
Introduzido| English | Significado |
|---|---|
| incomplete combustion/ɪŋkəmˈpliːt kəmˈbʌstʃn/ | combustão incompleta |
| particulates/pəˈtɪkjʊleɪts/ | partículas |
| global dimming | escurecimento global |
| acid rain/ˈæsɪd reɪn/ | chuva ácida |
Does sulfur-free fuel remove every engine pollutant?
- Removing sulfur targets sulfur dioxide. The air entering a hot engine still contains nitrogen and oxygen, and the fuel may still contain carbon.
- Predict products from all reactant sources and the conditions. Then match each pollutant to its effect and a control that actually targets it.
Start with fuel elements and oxygen supply
- Complete combustion of a pure hydrocarbon with sufficient oxygen produces carbon dioxide and water. Limited oxygen can cause incomplete combustion 不完全燃烧, making carbon monoxide and soot as well as some carbon dioxide/water.
- Pure hydrogen plus oxygen forms water, not carbon dioxide: no carbon atoms enter in those reactants. Fuel sulfur burns to sulfur dioxide; at high temperature, nitrogen and oxygen in air can react to form nitrogen oxides.
| Given fuel or condition | Supported product prediction |
|---|---|
| Pure hydrogen and oxygen | Water; no carbon source |
| Methane, sufficient oxygen | Carbon dioxide and water |
| Methane, limited oxygen | Carbon monoxide and/or soot possible |
| Sulfur impurity burned in air | Sulfur dioxide |
| High-temperature engine, nitrogen-free fuel | Nitrogen oxides still possible from air |
O que se forma quando apenas hidrogênio puro e oxigênio reagem por combustão completa?
Difficulty 1/5 · 100 coins + a small bonus on first completion today
Água se forma na reação 2H₂ + O₂ → 2H₂O. Nenhum átomo de carbono é fornecido, portanto esses reagentes sozinhos não podem produzir dióxido de carbono, monóxido de carbono ou fuligem.
Separate toxic gas from particles
- Carbon monoxide is toxic, colourless and odourless. It reduces the blood's ability to transport oxygen; absence of smell cannot establish its absence.
- Particulates 颗粒物 include carbon particles and unburned hydrocarbons. They can harm health and reduce sunlight reaching the surface, causing global dimming 全球变暗. A particle filter does not necessarily remove a gas such as carbon monoxide.
Nomeie o gás tóxico, incolor e inodoro contendo carbono resultante de combustão incompleta.
Difficulty 1/5 · 100 coins + a small bonus on first completion today
Monóxido de carbono reduz o transporte de oxigênio no sangue e não pode ser descartado pelo odor. Dióxido de carbono é um gás diferente com papel principal diferente neste tópico.
Explain nitrogen and sulfur oxide effects
- Sulfur dioxide and nitrogen oxides cause respiratory problems and acid rain 酸雨. Acid rain can damage aquatic ecosystems, trees and some stone/buildings.
- Nitrogen oxides can form from hot air even when the fuel contains no nitrogen. Sulfur-free fuel can lower sulfur dioxide without removing that source of nitrogen oxides.
Associe cada poluente ou efeito à descrição correta.
Difficulty 2/5 · 140 coins + a small bonus on first completion today
CO é distinto do CO estufa₂. Partículas reduzem a luz solar entrante; gases de efeito estufa afetam a radiação infravermelha superficial emissiva.
Check a proposed treatment by atom counts
- With the supplied reactants, $CaO+SO_2\rightarrow CaSO_3$: the product is calcium sulfite. Claiming only these reactants make $CaSO_4$ loses oxygen conservation; extra oxygen is needed for sulfate.
- A supplied converter reaction is $2CO+2NO\rightarrow2CO_2+N_2$. Both sides have two carbon, two nitrogen and four oxygen atoms. It removes carbon monoxide and nitrogen monoxide but produces carbon dioxide, so it does not eliminate greenhouse-gas impact.
Better oxygen supply can reduce incomplete-combustion products. It does not remove carbon dioxide from complete carbon-fuel combustion. Always distinguish a reduction in one pollutant from a reduction in every emission.
Em 2CO + 2NO → 2CO₂ + N₂, quantos átomos de oxigênio são representados em cada lado?
Difficulty 2/5 · 140 coins + a small bonus on first completion today
Oxigênio nos reagentes =2×1 de CO +2×1 de NO =4 átomos. Oxigênio nos produtos =2×2 de CO₂ =4 átomos. N₂ não contém oxigênio; a equação conserva átomos.
Evaluate controls with the right radiation model
- Particle filters and sulfur-free fuel can reduce particle and sulfur-dioxide effects. Remaining concerns include carbon dioxide from carbon fuels, carbon monoxide if combustion is incomplete and nitrogen oxides from hot air; measure each relevant emission under comparable conditions.
- Global dimming concerns particles reducing incoming sunlight. Greenhouse warming concerns gases absorbing outgoing surface infrared and emitting in all directions. These are different processes; do not assume dimming safely cancels warming.
“All climate and breathing problems are solved by a particle filter” is false. A filter targets particles; remaining gases have different sources, chemistry and effects.
Fuel elements + oxygen supply + temperature determine possible products. State the pollutant, its effect and a suitable control, and check reaction atom counts before accepting a treatment claim.
Um filtro de partículas remove todos os problemas climáticos e respiratórios da exaustão de um motor.
Difficulty 1/5 · 100 coins + a small bonus on first completion today
Ele alinha-se às partículas. CO₂ pode permanecer da combustão de combustível de carbono, CO pode formar-se se a combustão for incompleta, e NOₓ pode formar-se do ar quente. Esses gases têm química e efeitos diferentes.
Quais duas explicações limitam corretamente uma afirmação sobre controle de escapamento?
Difficulty 2/5 · 140 coins + a small bonus on first completion today
Nitrogênio pode vir do ar, e gases podem passar por um filtro de partículas. Oxigênio suficiente pode reduzir CO/fuligem, mas a combustão completa de combustível com carbono ainda produz CO₂.