化工专业英语试题三,英译汉.(40 分) 1,An atom consists of a very small posi
化工专业英语试题
三,英译汉.(40 分)
1,An atom consists of a very small positively charged nucleus,surrounded by negative electrons held by electrostatic attraction.The motion of electrons changes when chemical bonds are formed,nuclei being unaltered.
2,Electronegativity is the power of an atom to attract electrons to itself in a chemical bond.Different numerical estimates agree on qualitative trends:electronegativity increases from left to right along a periodic table.Elements of low electronegativity are called electropositive.Electropositive elements form metallic solids.Electronegative elements form molecules or polymeric solid with covalent bonds.
3,Molecular orbitals are wavefunctions for electrons in molecules,often formed by the linear combination of atomic orbitals approximation.Overlappling atomic arbitals can give bonding and antibonding molecular orbitals.Electrons in bonding molecular orbitals have an increased probability of being in the region between the nuclei.
四,中译英.(15 分)
1,生锈的化学过程并不十分清楚,但已确认铁锈是氧和湿气作用生成的水合氧化铁,并且,由于微量的二氧化碳的存在生锈的速度将显著加快.x0c
2,饱和烃尽管可以发生象卤代这样的化学反应,但是总的化学反应活性相对较低,相 比之下,不饱和烃易发生加成反应,芳香族化合物则往往容易发生取代反应.
3,气体溶质的分压与其在溶液中的溶解度之间的关系可用亨利定律来描述,即气体 溶质的分压与其在溶液中的溶解度成正比.
4,色谱法能将不同的组分分离是基于被分离物质的溶液中各组分与色谱中固定相和 流动相之间的亲合力存在差异.
5.对于液体有机物的分离和提纯来说,应用最为广泛的方法是蒸馏,其中包括常压蒸 馏,减压蒸馏,水蒸汽蒸馏和分馏.x0c