首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
Petroleum products,such as gasoline,kerosine,home heating oil,residual fuel oil,and lubricating oils, come from one source-crude
Petroleum products,such as gasoline,kerosine,home heating oil,residual fuel oil,and lubricating oils, come from one source-crude
admin
2015-01-09
46
问题
Petroleum products,such as gasoline,kerosine,home heating oil,residual fuel oil,and lubricating oils, come from one source-crude oil found below the earth’s surface,as well as under large bodies of water, from a few hundred feet below the surface to as deep as 25,000 feet into the earth’s interior. Sometimes crude oil is secured by drilling a bole through the earth,but more dry boles are drilled than those producing oil. Pressure at the source or pumping forces crude oil to the surface.
Crude oil wells flow at varying rates,from ten to thousands of barrels per hour. Petroleum products are always measured in 42-gallon barrels.
Petroleum products vary greatly in physical appearance:thin,thick,transparent or opaque,but regardless, their chemical composition is made up of only two elements:carbon and hydrogen,which form compounds called hydrocarbons. Other chemical elements found in union with the hydrocarbons are few and are classified as impurities. Trace elements are also found,but these are of such minute quantities that they are disregarded. The combination of carbon and hydrogen forms many thousands of compounds which are possible because of the various positions and joinings of these two atoms in the hydrocarbon molecule.
The various petroleum products are refined from the crude oil by heating and condensing the vapors. These products are the so-called light oils,such as gasoline,kerosene,and distillate oil. The residue remaining after the light oils are distilled is known as heavy or residual fuel oil and is used mostly for bunting under boilers. Additional complicated refining processes rearrange the chemical structure or the hydrocarbons to produce other products, some of which are used to upgrade and increase the octane(辛烷)rating of various types of gasoline.
Many thousands of hydrocarbon compounds are possible because_____.
选项
A、the petroleum products vary greatly in physical appearance
B、complicated refining processes rearrange the chemical structure
C、the two atoms in the molecule assume many positions
D、the pressure needed to force it to the surface causes molecular transformation
答案
C
解析
文章第三段解释了碳和氢结合能形成数千种化合物的原因是“the various positions and joinings ofthese two atoms in the hydrocarbon molecule”,选项C符合文意。
转载请注明原文地址:https://kaotiyun.com/show/U2LO777K
0
考博英语
相关试题推荐
Effortstoreachtheinjuredmenhavebeen______becauseofasuddendeteriorationinweatherconditions.
Peoplethinkingabouttheoriginoflanguageforthefirsttimeusuallyarriveattheconclusionthatitdevelopedgraduallyas
Shouldwecareifover150knownspeciesofanimalshave【1】fromtheearthinthelastfiftyyears?Shouldwebeconcernedthatt
PsychologistAlfredAdlersuggestedthattheprimarygoalofthepsyche(精神)wassuperiority.Although【1】hebelievedthatindividu
Humanchoice,nottheintrinsiccontentofscience,determinestheoutcomeandscientists,ashumanbeings,thereforehaveaspe
TheEnglishlanguagecontainsa(n)______ofwordswhicharecomparativeseldomusedinordinaryconversation.
ThehistoryofAfrican—Americansduringthepast400yearsistraditionallynarrated【1】anongoingstruggleagainst【2】andindiffe
Unlikemostsports,whichevolvedovertimefromstreetgames,basketballwasdesignedbyonemantosuitaparticularpurpose.
Itusedtobesostraightforward.Ateamofresearchersworkingtogetherinthelaboratorywouldsubmittheresultsoftheirres
A、conditionsB、situationsC、occasionsD、instancesC四个选项的意思是:A项conditions“条件,社会地位”;B项situations“境遇,位置”;C项occasions“场合,时机,机会”;D项in
随机试题
Everybodywastouched______wordsaftertheyheardhermovingstory.
(2004年第49题)下列符合心电图诊断窦性停搏的是
A、实体觉检查B、两点辨别觉检查C、皮肤定位觉检查D、震动觉检查E、运动觉检查被检者闭目,检查者轻轻夹住被检者的手指或足趾两侧,上下移动5°左右,令被检者说出“向上”或“向下”
下列关于微囊的叙述错误的是()
企业交纳的下列税金中,可以不通过“应交税金”科目核算的是()。
我国采用定牌生产出口商品时,在商品或其包装上只能使用买方指定的商标或品牌,而不能注明“中国制造”字样。()
趋势线被突破后,这说明()。
(2013年单选8)马克思指出:立法者应该把自己看作一个自然科学家。对此,下列理解正确的是()。
求I=cos(x+y)|dxdy,其中D={(x,y)|0≤x≤,0≤y≤}.
We’llvisitEuropenextyearprovidedwehaveenoughmoney.
最新回复
(
0
)