皮皮学,免费搜题
登录
搜题
【简答题】
Chemistry is the study of matter and its interactions with other matter and energy. Chemistry is related to several areas of science , such as biology , geology , and medicine.There are many practical uses of chemistry in the world around us. Chemists have developed synthetic fibers used in the textile industry . Cooking is another practical use of chemistry When you make a cake , several different substances are mixed and baked , which results in a new substance. Chemistry dates back to prehistoric times . Scientists believe the first chemical reaction discovered by man was the burning of wood . Chemistry was first practiced by women . To prepare food , they mixed and boiled ingredients . They learned how to separate solids and liquids . Fermentation was used to make different types of food and a variety of drinks. Salt was probably one of the first chemicals used. Salt was used for a variety of purposes like preserving foods, mummification, and making pottery. Salt was also used as a medicine in ointments, powders, and syrups. Other early chemicals were plant and animal dyes. Ancient cultures studied the nature of substances and produced useful compounds. Most of their discoveries were found by accident. Others were found by trial and error. The earliest evidence of chemistry was found on stone tablets dating back to 3,000 B.C. It records women making perfume. Chemistry as a modern science began in the 17th century. It was based on the scientific method. In the 1800s, chemistry was divided into three main branches: inorganic, organic, and physical chemistry. Inorganic chemistry was the study of compounds without carbon. Organic chemistry was the study of substances containing carbon. Physical chemistry dealt with the study of heat, electricity, and other forms of energy in chemical processes. Later, two more branches of chemistry were added: analytical chemistry and biochemistry. Chemistry is important to our day-to-day lives. It affects everything in our world from the home to the environment. We use it to create hair and skin care products. It makes leaves change color in the fall. An interesting use of chemistry is the making of artificial snow used by ski lodges and the motion picture industry. Scientists believe chemistry is the best solution to many of the problems we face in today ’ s world.
拍照语音搜题,微信中搜索"皮皮学"使用
参考答案:
参考解析:
知识点:
.
..
皮皮学刷刷变学霸
举一反三
【单选题】按照我国保险法的规定。人寿保险的索赔时效和人寿保险以外的其他保险的索赔时效分别为。
A.
五年和两年
B.
五年和三年
C.
四年和两年
D.
四年和三年
【单选题】当剖视图按投影关系配置,中间又没有其他图形隔开时,可省略() 。
A.
箭头
B.
标注
C.
剖面符号
D.
名称
【单选题】哪种属于软组织损伤?( )
A.
脱位
B.
.挫伤
C.
内脏破裂
D.
.脑震荡
【判断题】加工中心中最为常见的换料装置是托盘交换器( Au tom atic Pall etChanger- APC),它不仅是加工系统与 物流系统间的工件输送接口,也起物流系统工件缓冲站的作用。
A.
正确
B.
错误
【判断题】( )加工中心中最为常见的换料装置是托盘交换器 (Automatic Pllet Changer Y一APC),它不仅是加工系统与物流系统间的工件输送接口,也起物流系统工件缓冲站的作用。
A.
正确
B.
错误
【多选题】唐卡流派众多,大概可分为 等多种流派。
A.
噶当尼泊尔派
B.
岗巴派
C.
钦则派和勉塘派
D.
噶孜派及尼瓦尔派
【判断题】当剖视图按投影关系配置,中间又没有其他图形隔开时,可省略箭头
A.
正确
B.
错误
【单选题】当剖视图按投影关系配置,中间又没有其他图形隔开时,可省略( )。
A.
箭头
B.
标注
C.
剖面符号
D.
视图名称
【单选题】我国《保险法》规定,人寿保险以外的其他保险的被保险人或受益人,对保险人请求赔偿或给付保险金的权利,自其知道保险事故发生之日起( )不行使而消灭。
A.
五年
B.
四年
C.
三年
D.
二年
【简答题】哪种属于软组织损伤?()
相关题目: