2019年12月大学英语六级第一套真题及答案_2019年12月大学英语六级阅读晨读美文：HydrogenandIndustries

【#四六级考试# 导语】®文档大全网英语四六级频道为备考英语六级的同学们整理了2019年12月英语六级阅读晨读美文：Hydrogen and Industries ，希望可以为大家带来帮助，预祝大家高分通过大学英语六级考试。

　Hydrogen and Industries

　　Hydrogen, the lightest and simplest of the elements, has several properties that make it valuable for many industries. It releases more heat per unit of weight than any other fuel. In rocket engines, tons of hydrogen and oxygen are burned, and hydrogen is used with oxygen for welding torches that produce temperatures as high as 4, 000 degrees F and can be used in cutting steel. Fuel cells to generate electricity operate on hydrogen and oxygen. Hydrogen also serves to prevent metals from tarnishing during heat treatments by removing the oxygen from them. Although it would be difficult to remove the oxygen by itself, hydrogen readily combines with oxygen to form water, which can be heated to steam and easily removed. Hydrogen is also useful in the food industry for a process know as hydrogenation. Products such as margarine and cooking oils are changed from liquids to semisolids by adding hydrogen to their molecules. Soap manufacturers also use hydrogen for this purpose. Hydrogen is also one of the coolest refrigerants. It does not become a liquid until it reaches temperatures of -425 degrees F. Pure hydrogen gas is used in large electric generators to cool the coils. In addition, in the chemical industry, hydrogen is used to produce ammonia, gasoline, methyl alcohol, and many other important products.

2019年12月大学英语六级阅读晨读美文：Hydrogen and Industries.doc

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