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請大家打救我啦!!!moler mass問題真係好難!!!!!!

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諗左勁耐都唔識,雖然長左d,星期一考啦!!!希望大家幫幫我啦~ When Na burns in air, a mixture of sodium peroxide and sodium oxide(Na2O)is produced. (a)sodium peroxide contains 58%by mass of sodium. Calculate the empirical formula of sodium peroxide (b)The molar mass of sodium peroxide is78.0g mol/1. Deduce its chemical formula.

最佳解答:

(a) Let X be the mass of sodium peroxide Number of mole of sodium in sodium peroxide = X (58%) / 23.0 Number of mole of oxygen in sodium peroxide = X (42%) / 16.0 Number of mole of sodium : Number of mole of oxygen = [X (58%) / 23.0] : [X (42%) / 16.0] = 1 : 1 The empirical formula of sodium peroxide is NaO (b) Let n be the number of sodium ions in a formula unit of sodium peroxide n (23.0 + 16.0) = 78.0 n = 2 The chemical formula of sodium peroxide is Na2O2

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