Empirical Formula of Vanillin

Question

Vanillin, a flavoring agent, is made up of carbon, hydrogen, and Oxygen atoms. When a sample of Vanillin weighing 2.500g burns in Oxygen, 5.79 g of carbon dioxide and 1.18 g of water are obtained. What is the empirical formula of Vanillin

Answer 1

@ 12 grams carbon to 44 grams CO2, find grams of carbon:

5.79 g CO2@ 12 grams Carbon / 44 g CO2 = 1.58 gramss carbon



@ @ 2.02 grams Hydrogen to 18.02 grams H2O, find grams hydrogen:

1.18 grams water @ 2.02g H / 18.02 g H2O = 0.132 grams Hydrogen

@ 2.50 grams total - 1.58 g Carbon & - 0.132 g hydrogen ....=

0.79 grams oxygen

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find moles:

1.58 gramss carbon @ 12 g/mol = 0.132 moles

0.132 grams Hydrogen  @ 1g/mol = 0.132 moles

0.79 grams oxygen @ 16 g/mol = 0.0494 moles

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ratio of moles:

0.132 moles / 0.0494 = 2.67 moles C

0.064 moles / 0.0494 =  2.67 mole H

0.049 moles / 0.0494 = 1 mole O

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multiplying 2.67 ( aka 2 & 2/3) by 3 gives whole #'s

2.67 moles C  times 3 = 8 moles C

2.67 mole H times 3 = 8 moles H

1 mole O times 3 = 3 moles O

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your answer is C8H8O2

P.S. on your washing soda question I had the right answer, first...

when you wish a further explanation e-mail me