Lê Quỳnh  Anh

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions.

The Development of Refrigeration

          Cold storage, or refrigeration, is keeping food at temperatures between 32 and 45 degrees F in order to delay the growth of microorganisms - bacteria, molds, and yeast - that cause food to spoil. Refrigeration produces few changes in food, so meats, fish, eggs, milk, fruits, and vegetables keep their original flavor, color, and nutrition. Before artificial refrigeration was invented, people stored perishable food with ice or snow to lengthen its storage time. Preserving food by keeping it in an ice-filled pit is a 4,000-year-old art. Cold storage areas were built in basements, cellars, or caves, lined with wood or straw, and packed with ice. The ice was transported from mountains, or harvested from local lakes or rivers, and delivered in large blocks to homes and businesses.

          Artificial refrigeration is the process of removing heat from a substance, container, or enclosed area, to lower its temperature. The heat is moved from the inside of the container to the outside. A refrigerator uses the evaporation of a volatile liquid, or refrigerant, to absorb heat. In most types of refrigerators, the refrigerant is compressed, pumped through a pipe, and allowed to vaporize. As the liquid turns to vapor, it loses heat and gets colder because the molecules of vapor use energy to leave the liquid. The molecules left behind have less energy and so the liquid becomes colder. Thus, the air inside the refrigerator is chilled.

          Scientists and inventors from around the world developed artificial refrigeration during the eighteenth and nineteenth centuries. William Cullen demonstrated artificial refrigeration in Scotland in 1748, when he let ethyl ether boil into a partial vacuum. In 1805, American inventor Oliver Evans designed the first refrigeration machine that used vapor instead of liquid. In 1842, physician John Gorrie used Evans's design to create an air-cooling apparatus to treat yellow-fever patients in a Florida hospital. Gorrie later left his medical practice and experimented with ice making, and in 1851 he was granted the first U.S. patent for mechanical refrigeration. In the same year, an Australian printer, James Harrison, built an ether refrigerator after noticing that when he cleaned his type with ether it became very cold as the ether evaporated. Five years later, Harrison introduced vapor-compression refrigeration to the brewing and meatpacking industries.

          Brewing was the first industry in the United States to use mechanical refrigeration extensively, and in the 1870s, commercial refrigeration was primarily directed at breweries. German-born Adolphus Busch was the first to use artificial refrigeration at his brewery in St. Louis. Before refrigeration, brewers stored their beer in caves, and production was constrained by the amount of available cave space. Brewing was strictly a local business since beer was highly perishable and shipping it any distance would result in spoilage. Busch solved the storage problem with the commercial vapor- compression refrigerator. He solved the shipping problem with the newly invented refrigerated railcar, which was insulated with ice bunkers in each end. Air came in on the top, passed through the bunkers, and circulated through the car by gravity. In solving Busch's spoilage and storage problems, refrigeration also revolutionized an entire industry. By 1891, nearly every brewery was equipped with mechanical refrigerating machines.

          The refrigerators of today rely on the same basic principle of cooling caused by the rapid evaporation and expansion of gases. Until 1929, refrigerators used toxic gases - ammonia, methyl chloride, and sulfur dioxide - as refrigerants. After those gases accidentally killed several people, chlorofluorocarbons (CFCs) became the standard refrigerant. However, they were found to be harmful to the earth's ozone layer, so refrigerators now use a refrigerant called HFC 134a, which is less harmful to the ozone.

Artificial refrigeration involves all of the following processes EXCEPT______.

A. the pumping of water vapor through a pipe.

B. the rapid expansion of certain gases.

C. the evaporation of a volatile liquid.

D. the transfer of heat from one place to another.

Dương Hoàn Anh
20 tháng 12 2019 lúc 2:29

Đáp án A

Làm lạnh nhân tạo bao gồm tất cả các quy trình sau đây, ngoại trừ______.

A. nước được bơm qua đường ống.

B. sự giãn nở nhanh chóng của một số loại khí nhất định.

C. sự bốc hơi của các chất lỏng dễ bay hơi.

D. sự truyền nhiệt từ nơi này sang nơi khác.

Dẫn chứng ở đoạn 2: “Artificial refrigeration is the process of removing heat from a substance, container, or enclosed area, to lower its temperature. The heat is moved from the inside of the container to the outside (D). A refrigerator uses the evaporation of a volatile liquid (C), or refrigerant, to absorb heat . In most types of refrigerators, the refrigerant is compressed, pumped through a pipe, and allowed to vaporize. As the liquid turns to vapor, it loses heat and gets colder because the molecules of vapor use energy to leave the liquid (B). The molecules left behind have less energy and so the liquid becomes colder. Thus, the air inside the refrigerator is chilled” – (Làm lạnh nhân tạo là quá trình loại bỏ nhiệt từ các chất, thùng chứa hoặc các khu vực xung quanh để làm giảm nhiệt độ. Nhiệt sẽ di chuyển từ bên trong các thùng chứa đi ra bên ngoài. Tủ lạnh lợi dụng sự bốc hơi của chất lỏng dễ bay hơi hoặc chất làm lạnh để hấp thụ nhiệt. Trong hầu hết các loại tủ lạnh, chất làm lạnh được nén, bơm qua đường ống, và bốc hơi. Khi chất lỏng chuyển qua thể hơi, nó sẽ mất dần nhiệt và trở nên lạnh dần do các phân tử sử dụng năng lượng để thoát lỏng. Các phân tử đó sẽ để lại phía sau ít năng lượng hơn và do đó chất lỏng sẽ trở nên lạnh dần. Như vậy, không khí trong tủ lạnh đã được làm lạnh).

Ngoài ra, ý A sai do trong đoạn trên có nhắc tới: “chất làm lạnh” được bơm qua các ống dẫn chứ không phải “nước”.

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