14/5chem測驗啦..仲有兩日..希望大家教下我點答呢條先拎足分~(chem段落)廿分一條~~

The previous one is no the most suitable one.
If It is A-level type question, you should have this answer.

1. Using a 25cm3 pipette to extract 25cm3 diluted hydrochloric acid from
the solution of HCl with unknown concentration. Add this 25cm3 HCl into
a 250cm3 volumetric flask. Add distilled water until the water level attains the graduation mark. shake the solution.
(or meniscus (彎液面) attains the graduation mark)

2. Use an electrical balance to measure the weight of sodium carbonate.
Afterwards, add this mass into 250cm3 distilled water. use a stirrer to stir the
solution until all granules of sodium carbonate dissolve in water.

3. Fill the burette with sodium carbonate. extract 25cm3 HCl from the volumetric flask to conical flask

4. use methyl orange as indicator, titirate HCl against sodium carbonate

5. stop titrate until the color of the solution in conical flask turns yellow

6. measure the volume of Na2CO3 required

7. repeat the experiment to obtain a list of data about the concentration of sodium carbonate required.

8. calculation: mass of sodium carbonate and its volume are known.
concentration of it can be obtained. volume of HCl=25cm3
it is the reaction between carbonate and dilute acid
the calculated concentration X10 = the concentration of HCl

2008-05-20 10:50:51 補充：
if you don't know how to calculate the result
ask me ok?

已知碳酸鈉體積濃度

開始酸鹼滴定

得到碳酸鈉、鹽酸的體積

開始計算~~用公式MV=MV

算出答案

買不到滴定管~~我送給你

記得做兩次以上~~準確率

有不清楚再補充！