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单选题 A ( ) is a substance that speeds up a chemical reaction but does not enter into the reaction itself
学科：专业英语
时间：2023-10-27 14:38:37
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题目1单选题
The problem whether natural rubber ( ) a polymer with linear chain molecules has been solvedA. hasB. haveC. isD. are
题目2单选题
A ( ) is a substance that speeds up a chemical reaction but does not enter into the reaction itselfA. compoundB. moleculeC. catalystD. functional group
题目3单选题
Alkanes undergo reactions such as cracking, alkylation, oxidation, ( ), nitration and so onA. halogenB. halogenateC. halideD. halogenation
题目4单选题
Organic compounds will not usually ( ) an electric current when in solutionA. conductB. conductingC. transportD. transporting
题目5单选题
It has long been the practice to attempt the ( ) of natural products in the laboratory once their structures had been determinedA. discoveryB. inventionC. estimationD. synthesis
题目6单选题
Pairs of shared electrons must spin in ( ) directionsA. sameB. similarC. oppositeD. parallel
题目7单选题
Tertiary alcohols are resistant to ( )A. oxideB. oxidationC. sulfideD. sulfate
题目8单选题
In contrast to inorganic compounds, the molecular attraction of organic compounds is weak, so organic compounds are usually ( ) and possess low melting pointsA. non-volatileB. volatileC. biodegradableD. flammable
题目9单选题
In their work they pay much attention to the combination of theory with ( )A. practiceB. experimentC. experienceD. phenomenon
题目10单选题
The two pairs of electrons of oxygen may be shared with one carbon alone forming a ( ) bond(>C=O)A. singleB. doubleC. TripleD. covalent
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