f4 化學幾問 - Ans.fyi 參考答案

f4 化學幾問

2014-02-22 11:51 pm

1.Is it all carbonate compounds dissolve in water only calcium carbonate does not?

2.Is it all metal carbonate occur effervescence when react with acid ?

3.There are two bottles of acids, both PH equal to 2. One of the solution is strong while another one is weak acid. How to distinguish the two acid solution by using PH paper litmus solution phenolphthalein and distilled water.

4.Which of the following acid and solutions has the lowest PH ?
A 300cm3 of 1.00X10-3 mol dm3 H2CO3
B 100cm3 of 1.00X10-4 mol dm3 H2CO3
C 100cm3 of 1.00X10-3 mol dm3 H2SO4
D 10cm3 of 1.00X10-4 mol dm3 H2SO4

更新1:

可唔可以講解下第4條點解係c呀?

回答 (1)

用戶4366

2014-02-23 2:44 am

✔ 最佳答案

1. No. Only potassium, sodium, and ammonium carbonate are soluble.

2. Yes, they do.

3. Dilute a strong acid solution by 10 times will increase its pH by 1.

Dilute a weak acid solution by 10 times will ??????????????

The degree of ionization should increase when a solution is diluted.

So, the increase of pH should be less than 1.

4. C

2014-02-23 20:15:58 補充：
4.Which of the following acid and solutions has the lowest PH ?
A 300cm3 of 1.00X10-3 mol dm3 H2CO3

H₂CO₃ 是弱酸(weak acid) pH 唔會很低。

B 100cm3 of 1.00X10-4 mol dm3 H2CO3

H₂CO₃ 是弱酸(weak acid) pH 唔會很低。

2014-02-23 20:17:51 補充：
C 100cm3 of 1.00X10-3 mol dm3 H2SO4

H₂SO₄ 是强酸(strong acid)，第一步電離(ionization)是100%，所以這個溶液的pH略低於3。

D 10cm3 of 1.00X10-4 mol dm3 H2SO4

H₂SO₄ 是强酸(strong acid)，第一步電離(ionization)是100%，所以這個溶液的pH略低於4。

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