✔ 最佳答案
Picture 1: It tells the mass of 2 mol Mg & 5 mol Al mixture is bigger then
3mol Zn mixture's.
In my calculation, it is wrong.
The mass of 2 mol Mg & 5 mol Al mixture should be 48.6g + 135g = 183.6g.
And, the mass of 3 mol Zn should be 196.2g.
Thus, the mass of 3 mol Zn is bigger then the mass of 2 mol Mg & 5 mol Al
mixture's.
The riddle can test students how to find the mass of a chemical compound by
using the formula weight & the mole.
* Some students misunderstand that a substance has the greatest mole means it is the heaviest between two substance.
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Picture 2: It tells 2M Ethanoic acid is stronger then 1M Hydrochloric acid.
In my answer, it is incorrect.
2M CH3COOH can produce 2M H+. However, in the fact, there is only 0.4% of CH3COOH can occur to ionize.
Thus, H+ mole which is produced from CH3COOH = 2M x 0.4% = 0.008M
The other side, hydrochloric acid approximately can ionize to H+ & Cl-.
Thus, 1M HCl solution contains 1M H+.
The concentration of H+ in 1M hydrochloric acid > >
The concentration of H+ in 2M CH3COOH solution.
1M hydrochloric acid must be stronger then 2M CH3COOH solution.
* Some students misunderstand that a great molar concentration of a acid
must mean it is a strong acid.
2008-04-10 22:56:00 補充：
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2008-04-10 22:56:45 補充：
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成日亂碼- -
2008-04-11 18:36:29 補充：
The questions for picture 1:
1. What do the picture tell?
2. Is it correction: "If the mole is the greastest between two substances, it should be the heaviest."?
3. Explain your Q.2 answer.
4. What does "Mole" represent to?
5. Correct the picture together with your calculations.
2008-04-11 18:36:48 補充：
The questions for picture 2:
2008-04-11 18:36:58 補充：
1. What is wrong with the picture?
2. Is it correction: "If the molar concentration of an acid is greater then 5M, it will be an strong acid."? Explain your answer.
2008-04-11 18:37:01 補充：
3. If the molar concentration of Acid A is greater than Acid B's, it means Acid A is stronger then Acid B? Explain your answer.
4. How many percentage of ethanoic acid occur to ionize?
5. Correct the picture with your calculations.
