Textbook Question
Serotonin is a compound that conducts nerve impulses in the brain. It contains 68.2% C, 6.86% H, 15.9% N, and 9.08% O. Its molar mass is 176 g/mol Determine its molecular formula.
3. Chemical Reactions
Molecular Formula
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A compound has an empirical formula of C2H5O and a molecular mass of 135 amu. What is the molecular formula?
A
C2H5O
B
C6H15O3
C
C4H10O2
D
C8H20O4
Verified step by step guidance1
Calculate the molar mass of the empirical formula C2H5O. Add the atomic masses of each element: Carbon (C) has an atomic mass of approximately 12 amu, Hydrogen (H) is about 1 amu, and Oxygen (O) is about 16 amu. Therefore, the molar mass of C2H5O is (2 * 12) + (5 * 1) + (1 * 16) amu.
Determine the ratio of the molecular mass to the empirical formula mass. Divide the given molecular mass (135 amu) by the molar mass of the empirical formula calculated in the previous step.
The result from the division in the previous step should be a whole number or very close to a whole number. This number indicates how many times the empirical formula must be multiplied to obtain the molecular formula.
Multiply the subscripts in the empirical formula C2H5O by the whole number obtained in the previous step. This will give you the molecular formula.
Verify that the molecular formula obtained has a molar mass that matches the given molecular mass of 135 amu by recalculating the molar mass of the proposed molecular formula.
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