Question

The chemical formula of lysine (a building block of proteins) is C6H14N2O2. Given that the formula mass of lysine is 146.19 amu, what is the % (m/m) composition of H in lysine?

(For your calculation, use atomic masses that have been rounded to the closest hundredths of an amu (two places to the right of the decimal point). Express your answer using only a number or numbers without text. Report your result in decimal notation and to the proper number of significant figures.)

Answer 1

.The aromic mass of hydrogen = 1.0079amu x 14 = 14.1106 amu

The atomic mass of carbon = 12.0107 amu x 6= 72.0642 amu

The atomic mass of oxygen = 15.999 amu.x 2 = 31.998 amu

The atomic mass of nitrogen = 14.0067 amu x 2 = 28.0134 amu

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146.182 amu

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formula mass matching with given mass of lysine molecule

MAss of 14 hydrgens present in the molecule = 1.0079amu x 14

= 14.1106 amu

so mass of total hydrogen present in the molecule = 14.1106 amu

so percent mass of hydrogen =   14.1106 amu x 100/ 146.19

= 9.65