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Title: What is the empirical formula for the compound? Post by: fioravme09 on Sep 23, 2012 A certain compound, is known to contain carbon and hydrogen. It might also contain oxygen. A 4.226 g sample of this compound was burned in pure oxygen gas. The measured amount of CO2 produced was 8.074 g, while that of H2O was 4.958 g. No other products were produced in the reaction.
2.202 grams of carbon were in the original sample and 0.5509 grams of hydrogen were in the original sample. What is the empirical formula?!! Please help. Ohh! I understand now! Thank you! :D Title: What is the empirical formula for the compound? Post by: rjandmj82 on Sep 23, 2012 Your sample definately contains Oxygen.
The law of conservation of mass tells us that there must be the same mass in the products as there were in the reactants. The mass of C + mass H in you products = 2.202 g + 0.5509 g = 2.753 g But you started with 4.226 g of compound, so the difference in mass must be Oxygen mass O = 4.226 g - 2.202 - 0.5509 = 1.473 g Oxyygen in the compound Now work out the moles of C, H and O that were in the sample moles = mass / molar mass moles C = 2.202 g / 12.01 g/mol = 0.1833 moles C moles H = 0.5509 g / 1.008 g/mol = 0.5462 moles H moles O = 1.473 g / 16.00 g/mol = 0.0921 moles O Arrange the moles in a ratio format moles C : moles H : moles O = 0.1833 : 0.5462 : 0.0921 Divide each number by the smallest number in the ratio to get it into a whole number ratio. C : H : O (0.1833 / 0.0921) : (0.5462/0.0921) : (0.0921/0.0921) = 2 : 6 : 1 Empirical formula C2H6O |