题目

聚硅酸铁是目前无机高分子絮凝剂研究的热点,一种用钢管厂的废铁渣(主要成分Fe3O4，含少量碳及二氧化硅)为原料制备的流程如下： （1）废铁渣进行“粉碎”的目的是          。  （2）①加热条件下酸浸时，Fe3O4与硫酸反应的化学方程式为 。  ②酸浸时,通入O2的目的是 。   （3）滤渣的主要成分为(填化学式)。  （4）“Fe3+浓度检测”是先用SnCl2将Fe3+还原为Fe2+；在酸性条件下，再用K2Cr2O7标准溶液滴定Fe2+(Cr2O72-被还原为Cr3+)，该滴定反应的离子 We have found plastic in the ocean and in animals. But for the first time, scientists have found plastic in human poop（粪便）,USA Today reported.The findings came from a study by scientists from Environment Agency Austria. The researchers followed eight healthy volunteers from different parts of the world. The volunteers wrote down what they ate for a week and then provided a stool sample（大便样本）for testing.Scientists found nine different types of plastic particles（ 颗粒）in the samples. “The smallest plastic particles are able to enter the bloodstream, the lymphatic system （淋巴系统）,and may even reach the liver（肝脏）”said Philipp Schwabl, who took part in the research.However, the scientists aren't sure if this plastic is harmful to humans. They're not sure how the plastic got into the volunteers' bodies, either. But most of the volunteers said they drank from plastic bottles and also ate seafood that could include plastic from ocean pollution.In fact, plastic is everywhere around us. Every year, about 8 million tons of plastic waste goes into the oceans. There, sunlight and waves break the plastic down to small particles. Most of the particles stay in the ocean. Others can spread into the soil and air. Could plastic in the air fall onto food and get into the human body?According to USA Today, 90 percent of sea salt sold in the world includes plastic. And even some top water has been found to have plastic particles in it.1.According to USA Today, what have scientists found for the first time?A.Plastic in the ocean. B.Plastic in animals.C.Plastic in human poop. D.Plastic in the soil.2.The researchers________according to the second paragraph.A.followed eight healthy volunteers. B.are from Environment Agency AustraliaC.wrote down what they ate for a week D.provided a stool sample for testing3.Paragraph 3 is written to tell us that________A.plastic particles can be a few different sizes B.plastic particles can reach many parts of our bodiesC.plastic can harm the lymphatic system D.plastic particles are inside all of us4.What can we infer （推断） from the study?A.Plastic does no harm to our bodies.B.The best way to deal with plastic waste is to burn it.C.People should stop drinking tap（水龙头）water.D.It can be hard to avoid plastic in food and drinks.