Chem equilibrium

2013-02-02 4:12 am

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I would like to ask question 25 (d). We have to caculate the molarity of zinc chloride formed. We know the no. of moles of it, but how can we know the volume of it? As we have to know both the no. of moles and the volume to caculate the molarity. Please help~~~~~Many thx~~~~

回答 (1)

用戶26240

2013-02-02 4:43 am

✔ 最佳答案

25.
(a)(i)
No. of moles of HCl used = 1.0 x (50/1000) = 0.05 mol

(a) (ii)
No. of moles of H2 formed = 600/24000 = 0.025 mol

(b)
Zn+ 2HCl → ZnCl2 + H2
No. of moles of H2 formed = 0.025 mol
No. of moles of Zn reacted = 0.025 mol
Mass of Zn reacted = 65.4 x 0.025 = 1.635g

(c)
Number of Zn atoms reacted = 0.025 x (6.02 x 10²²) =1.505 x 10²²

(d)
Assume that the volume of solution remains unchanged during the reaction.
Then, volume of the final solution = volume of HCl used = 50 cm³ = 0.05dm³

Zn+ 2HCl → ZnCl2 + H2
No. of moles of H2 formed = 0.025 mol
No. of moles of ZnCl2 formed = 0.025 mol

Molarity of ZnCl2 formed = 0.025/0.05 = 0.5 mol dm⁻³

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