chem! (40 points)reacting mass @ 新聞雲

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chem! (40 points)reacting mass

發問:

1a)When iron(lll) hydroxide was heated to a high temperature, iron(lll) oxide was formed.2Fe(OH)3-------Fe2O3+3H2OCalculate the maximum mass of water formed from 5.35g of iron(lll) hydroxide.b)Anoher oxide of iron consist of 72.4% iron by mass.Calculate the empirical formula of this... 顯示更多 1a)When iron(lll) hydroxide was heated to a high temperature, iron(lll) oxide was formed. 2Fe(OH)3-------Fe2O3+3H2O Calculate the maximum mass of water formed from 5.35g of iron(lll) hydroxide. b)Anoher oxide of iron consist of 72.4% iron by mass. Calculate the empirical formula of this oxide. (Relative atomic massws: H=1.0, O=16.0,Fe=55.8)

最佳解答:

1a) When iron(lll) hydroxide was heated to a high temperature, iron(lll) oxide was formed. 2Fe(OH)3 → Fe2O3 + 3H2O Calculate the maximum mass of water formed from 5.35 g of iron(lll) hydroxide. b) Another oxide of iron consist of 72.4% iron by mass. Calculate the empirical formula of this oxide. (Relative atomic massws: H = 1.0, O = 16.0, Fe = 55.8) a) 2Fe(OH)3 → Fe2O3 + 3H2O Mole ratio Fe(OH)3 : H2O = 2 : 3 Molar mass of Fe(OH)3 = 55.8 + 3(16 + 1) = 106.8 g /mol No. of moles of Fe(OH)3- used = 5.35/106.8 = 0.05009 mol Maximum no. of moles of H2-O formed = 0.05009 x (3/2) = 0.07514 mol Molar mass of H2O = 1x2 + 16 = 18 g /mol Maximum mass of H2O formed = 0.07514 x 18 = 1.35 g b) Mole ratio Fe : O = 72.4/55.8 : (100 - 72.4)/16 = 1.30 : 1.73 = 1 : 1.33 = 3 : 4 Empirical formula = Fe3O4

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