SPM Chemistry(化学）急急急～ Chemistry这俩题怎样做？

ArianaCullen

各位SPM 化学大侠请救救我，我这俩题题目来自SPM Chemistry paper 3 section C， 请帮帮忙， 小女刚上中四什么都不适应，成绩一落千丈，不知如何是好


9. (a) Figure below shows the symbol representing an atom of sodium

                    nucleon no. : 23
                    proton no. : 11
                    symbol of element: Na

Based on the information given, elaborate the structure of sodium atom. your answer should include the diagram of electron arrangement and number of subatomic particles in the sodium atom.    (4 marks)

(b) Organic compound X is a solid at room temperature and pressure. The melting point of X is less than 100°C.                                 

(i) Describe a laboratory experiment to determine the freezing point of solid X. your answer should consist of following.

--> List of materials and apparatus required
--> Diagram showing the set-up of apparatus
--> Procedure of the experiment
--> Tabulation of data
--> Interpretation of data              (10 marks)

(ii) Describe the changes occurred in the arrangement of molecules, attractive forces between the molecules and the energy content of compound X when it is cooled from 100°C to room temperature.   (6 marks)


10. (a) (i) What is a chemical formula? (1 mark)
            (ii) State the qualitative and quantitative information that a chemical equation can provide. (3 marks)
        
       (b) (i) Name a metal which is less reactive than hydrogen in the reactivity series. (1 mark)
             (ii) Describe a laboratory experiment to determine the empirical formula of the oxide of the metal named in (b)(i) above. (10 marks)

(c) Nowadays, most of the cars are equipped with airbags that sodium azide, NaN3. Sodium azide decomposes quickly when heated to produce nitrogen gas and sodium. The gas prodeced will expand the air bag.
Calculate the mass of sodium azide required to produce just enough nitrogen gas to inflate an air bag of volume 35 dm3 at room conditions. (relative atomic mass: N,14; Na, 23; Molar volume of gas at room conditions = 24 dm3 mol-1)    (5 marks)

XiaoL3i

其实这些题目我记得 有做过的= = 楼主用心点吧

冬眠者

楼主，我可以教你theory，但不想直接写答案给你，因为这样是学不到东西的。

~贤_雨~

好怀念阿

freebitch

楼主你的chemistry 现在还在第二课你就好追上去了！！
想当初我的chemistry 到了CHEMICAL EQUATION 那里就不会了，而且后面都会有用到Equition ！
不过你还是可以逃过不会equition 的命运，就是那些equation你要背起来～

xianchua

楼主没有去补习吗？

xianchua

虽然我spm chemistry 拿 A。。但我全都忘了

枇杷膏

3年前的我肯定可以帮你~哈哈哈哈~

=橙子=

lalazaza 发表于 2013-4-14 04:42 PM
不好意思，我对楼上的答案有些疑问，我们可以一起讨论。

(b) (i) Name a metal which is less reacti ...

因为我已经SPM毕业2年多了
所以我也不太记得


不过你说是对

我忽略了一点
忘记hydrogen 不是group 1
谢谢你的提醒

这题应该based on
K,Na, Ca, Mg, Al, Zn, Fe, Sn , Pb, H , Cu ,Ag


应该是拿后面两个

lalazaza

=橙子= 发表于 2013-4-14 02:53 PM
9. (a) Figure below shows the symbol representing an atom of sodium

                    nucleon n ...

不好意思，我对楼上的答案有些疑问，我们可以一起讨论。

(b) (i) Name a metal which is less reactive than hydrogen in the reactivity series. (1 mark)
（Na , K) 是 very reactive 的.
   Hydrogen 下的metal 都可以例如 copper, gold, silver.


      (ii) Describe a laboratory experiment to determine the empirical formula of the oxide of the metal named in (b)(i) above. (10 marks)
   楼主看参考书，多数给的例子是copper(II) oxide. 多是用hydrogen gas pass through 的。
   重点包括 :
1. Hydrogen gas is allowed to flow for 5-10 minutes to remove all the air.
2. Excess hydrogen gas is burnt and copper (II) oxide is heated strongly.