Questão FC170811
Text 1A1-I Hydrogen is viewed as a promising alternative to fossil fuel, but the methods used to make it either generate too much carbon dioxide or are too expensive. Rice Universi
Semântica e Significado de Vocábulos (Semantics)
CEBRASPE (CESPE) · 2023
Hydrogen is viewed as a promising alternative to fossil fuel, but the methods used to make it either generate too much carbon dioxide or are too expensive. Rice University researchers have found a way to harvest hydrogen from plastic waste using a low-emission method that could more than pay for itself.
By comparison, “green” hydrogen ⎯ produced using renewable energy sources to split water into its two component elements ⎯ costs roughly US$ 5 for just over two pounds. Though cheaper, most of the nearly 100 million tons of hydrogen used globally in 2022 was derived from fossil fuels, its production generating roughly 12 tons of carbon dioxide per ton of hydrogen.
The researchers exposed plastic waste samples to rapid flash Joule, bringing their temperature up to 3100 Kelvin. “We demonstrated that we are able to recover up to 68% of that atomic hydrogen as gas with a 94% purity,” Kevin Wyss said. “I hope that this work will allow for the production of clean hydrogen from waste plastics, possibly solving major environmental problems like plastic pollution and the greenhouse gas-intensive production of hydrogen by steam-methane reforming.”
Internet: <news.rice.edu> (adapted).
The word “itself” (last sentence of the first paragraph) refers back to “plastic”, meaning that plastic could pay for its cost.
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Comentário: A afirmação está ERRADA porque a palavra "itself" não se refere a "plastic", mas sim ao método de produção de hidrogênio que os pesquisadores desenvolveram. O texto menciona que esse método poderia "mais do que pagar por si mesmo", indicando que o custo do método em si é compensado pelos benefícios que ele traz, como a recuperação de hidrogênio a partir de resíduos plásticos. Portanto, "itself" refere-se à viabilidade econômica do novo método, e não ao plástico, que é apenas a matéria-prima utilizada no processo.
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