题干

用于金属焊接的某种焊条,其药皮由大理石、水泥、硅铁等配制而成.下列说法不正确的是(  )


A:生产水泥的原料是大理石、纯碱、石英,其组成一般为Na2O•CaO•6SiO2

B:Si与NaOH溶液反应的离子方程式为:Si+2OH﹣+H2O=SiO32﹣+2H2↑

C:焊接过程中,药皮在高温下产生了熔渣和使金属不被氧化的气体,该气体是CO2

D:经处理后的熔渣36.0g(仅含Fe2O3、Al2O3、SiO2),加入足量稀盐酸,分离得到11.0 g固体;滤液中加入过量NaOH溶液,分离得到21.4g固体;则此熔渣中Al2O3的质量分数为25%

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A

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    Madison Williams was studying in her bedroom in Dublin, Ohio, in August 2016 when the door burst open. It was her mother, Leigh Williams, with a(an)1 story: “A little boy fell into a septic tank (化粪池), and no one can 2him.” Then she made this3 of her 13-year-old daughter: Can you help?

    Madison and Leigh ran to a neighbor's yard, where they found the boy's 4mother and other adults surrounding a septic tank opening. Its diameter was5 wider than a basketball. The boy had 6 in and was drowning in the sewage (污水).

    Madison quickly7 the situation. She was the only one who could 8through the small hole. Without 9 she told the adults, “Lower me in.” Inside, the tank was dark, and the air10 In the process of finding the boy, her left wrist was injured by a hidden pole so11 that the hand was useless. But Madison went on skimming the surface of the sewage, hoping to 12 the boy. “Every once in a while, I'd see his little toes she says. “Then I would try to grab them.” After several failed13 she finally managed to grasp his foot tightly with her14 hand. “Pull me up!” she shouted to the others above. Ten minutes after Madison had entered the tank, she and the boy were15 out.

    But the boy wasn't out of16He had been taken away from oxygen long enough that he wasn't breathing. He was 17 on his side, and an adult gave him several hard beats on the 18 one right after the other, until the boy coughed up liquids. It was only when Madison heard him cry that she knew he was all right.

    It took Madison longer to 19 than the boy. She experienced months of physical treatment for her wrist, which, says neighbor Mary, made the girl's actions more 20.