F.3 Chem HW (高人幫手 20marks thx)

2010-12-11 8:34 pm

圖片參考：http://imgcld.yimg.com/8/n/HA06956289/o/701012110055013873425280.jpg

(a) What is X?

(b)Suggest how you can carry out the following conversions.
(i) Calcium carbonate to calcium oxide
(ii)Calcium carbonate to calcium chloride
(iii)Calcium oxide to X

(c)Two samples of white powder are calcium carbonate and calcium hydroxide.
(i)Describe a chemical test to show that both samples calcium compounds.
(ii)Describe a chemical test to distinguish the two compounds.

2.Describe briefly how you can distinguish the following pairs of compounds using simple chemical tests.
(a)potassium sulphate solid and calcium sulphate solid
(b)Ethanol and magnesium nitrate solution

3.Limestone, quicklime and slaked lime are all calcium compounds.
complete the following table.
Common name Chemical name Constituents elements
Limestone ? ?
Quicklime ??
Slaked lime ??

回答 (4)

用戶34026

2010-12-12 8:09 am

✔ 最佳答案

(a) Calcium hydroxide

(b)(i) Heat calcium carbonate strongly.
(ii)Add hydrochloric acid to calcium carbonate.
(iii)Add water to calcium oxide.

(c)(i)Clean 2 platinum wires with concentrated hydrochloric acid. Dip one wire into each sample. Heat the wires strongly in non-luminous flame. Brick red colour flame is observed for each wire, indicating the presence of calcium ion in both compounds.
(ii)Add hydrochloric acid to each compound. The one with gas bubbles formed is calcium carbonate. The one with no gas bubbles formed is calcium hydroxide.

(a)Add sodium hydroxide solution to both compounds. The one with white precipitates formed is calcium sulphate, the one with no observable changes is potassium sulphate.

(b)Add sodium hydroxide solution to both compounds. The one with white precipitates formed is magnesium nitrate, the one with no observable changes is ethanol.

3. Calcium carbonate | Calcium, carbon, oxygen
Calcium oxide | Calcium, oxygen
Calcium hydroxide | Calcium, hydrogen, oxygen

參考: Myself

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