chemistry fastttttt

[匿名]

2013-09-24 6:51 am

22.2g of a metallic chloride sample was mixed with silver nitrate solution. The precipitate of silver chloride, AgCl was filtered, washed and dried. 57.4g solid was obtained.
(a)Why should the precipitate be washed and dried?

(b)Calculate
(i)the mass of chloride ions in the precipitate.

(ii)the number of moles of chloride ions in the precipitate.

(iii)the mass of chloride ions in the metallic chloride sample.

(iv)the number of moles of chloride ions in the metallic chloride.

(c)(i)Find the mole ratio of metal to chlorine in the sample if the relative atomic mass of the metal
is 40.

(ii)Write the empirical formula of the metallic chloride (Use M as the symbol of the metal)

回答 (1)

用戶4366

2013-09-24 10:03 pm

✔ 最佳答案

a) Wash away any impurities and dry off water.

b) i) 57.4 X (35.5/(35.5+108)) = 14.2(g)
ii) 14.2 / 35.5 = 0.4 mole
iii) 0.4 X 35.5 = 14.2 (g)
iv)0.4 mole

c) i) Mass of metal = 22.2 - 14.2 = 8
No. of mole of metal = 8 / 40 = 0.2 mole
Mole ratio = 0.2 : 0.4
=1:2

ii) MCl2

2013-09-24 14:04:23 補充：
drive off water

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