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cyw1226 2013-8-22 12:46 AM

water crystallization

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thomas1126 2013-8-22 01:23 AM

你試都唔試下叫人點應你

chungkin81 2013-8-22 08:44 AM

First, write out the chemical equation for the neutralization reaction:
Na2CO3. nH2O(aq) + 2HCl(aq) --> 2NaCl(aq) + CO2(g) + (n + 1) H2O(l)
No. of moles of HCl = 0.10 x 23.50 / 1000 = 2.35 x 10^-3 mol
No. of moles of Na2CO3. nH2O in 25.0 cm3 solution = 2.35 x 10^-3 / 2 = 1.175 x 10^-3 mol
No. of moles of Na2CO3. nH2O in 250.0 cm3 solution = 1.175 x 10^-3 x 10 = 0.01175 mol

By using mass / Molar mass = no. of moles concept,
1.46 / (23 x 2 + 12 + 16 x 3 + 18n) = 0.01175
1.46 / (106 + 18n) = 0.01175
1.46 = 1.2455 + 0.2115n
n = 1.01 (round up to 1)

So the number of molecules of water of crystallization per formula unit of hydrated carbonate is 1.
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查看完整版本: water crystallization