Anonymous
Anonymous asked in 科學及數學化學 · 8 years ago

F.4 chem~!!!

我想問呢,咩系

1. dispersion force

2. dipole-dipole forces

3. hygengen bond

4. dative covalent bond

5. end-point

6. 點樣可以分到D molecules系polar定non-polar

Update:

其他都明,但系dative covalent bond都仲系唔系好明~哈哈

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  • 8 years ago
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    1.dispersion force is the force between non-polar molecule.It occurs only instantaneously when the electrons in a molecule concentrate in one side of the molecule.

    2.Dipole-dipole forces is the force between polar molecule.I exsit permanently because of the difference of the electronegativity between two atoms.

    3.Hydrogen bond is a bond formed between a hydrogen atom and a lone pair of electron of another molecule.

    4.Dative covalent bond is a bond formed in a covalent molecule in which the electrons of the bond pair are contributed by the same atom.

    5.End point is the stage at which the indicator changes colour shaply.(但呢個point只係講大約acid同alkali中和左,至於the point of the acid and alkali確實地中和左係叫equivalent point)

    6.You have to consider both the polarity of the bond in the molecule and the shape of the molecule.If the molecule do not contain any polar bond(the electronegativity between two atoms are the same or generally smaller than 0.5), then the molecule should be non-polar.

    On the other hand,if the molecule contain polar bond,we have to consider its shape , if it is symmetrical ,then it should be non-polar,if not,it should be polar.

    2013-05-12 00:29:35 補充:

    Dative covalent bond就感講好難明,不如我舉個例子。

    係NH3同HCl

    For NH3,N同H form 左三個covalent bonds之後,仲有一對lone pair of electrons。至於HCl個covalent bond,H同Cl各比出一粒electron黎form bond。

    NH3 and HCl會產生reaction,另HCl中H會將自己果粒electron比左Cl,令Cl有八粒electron。至於個H冇晒電子,就會由NH3果個lone pair(兩粒)比晒個H,H同N之間form果個bond就叫做dative covalent bond。

    Source(s): me, me
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