element mass fraction of isethionic acid ammonium salt

isethionic acid ammonium salt | elemental composition

Find the elemental composition for isethionic acid ammonium salt in terms of the atom and mass percents: atom percent = N_i/N_atoms × 100% mass percent = (N_im_i)/m × 100% Plan: • Write the chemical formula and gather atomic masses from the periodic table. • Determine values for N_i, m_i, N_atoms and m using these items. • Finally, compute the percents and check the results. Write the chemical formula: HOCH_2CH_2SO_3NH_4 Use the chemical formula to count the number of atoms, N_i, for each element and find the total number of atoms, N_atoms, per molecule: | number of atoms C (carbon) | 2 H (hydrogen) | 9 N (nitrogen) | 1 O (oxygen) | 4 S (sulfur) | 1 N_atoms = 2 + 9 + 1 + 4 + 1 = 17 Divide each N_i by N_atoms to calculate atom fractions. Then use the property that atom fractions must sum to one to check the work: | number of atoms | atom fraction C (carbon) | 2 | 2/17 H (hydrogen) | 9 | 9/17 N (nitrogen) | 1 | 1/17 O (oxygen) | 4 | 4/17 S (sulfur) | 1 | 1/17 Check: 2/17 + 9/17 + 1/17 + 4/17 + 1/17 = 1 Compute atom percents using the atom fractions: | number of atoms | atom percent C (carbon) | 2 | 2/17 × 100% = 11.8% H (hydrogen) | 9 | 9/17 × 100% = 52.9% N (nitrogen) | 1 | 1/17 × 100% = 5.88% O (oxygen) | 4 | 4/17 × 100% = 23.5% S (sulfur) | 1 | 1/17 × 100% = 5.88% Look up the atomic mass, m_i, in unified atomic mass units, u, for each element in the periodic table: | number of atoms | atom percent | atomic mass/u C (carbon) | 2 | 11.8% | 12.011 H (hydrogen) | 9 | 52.9% | 1.008 N (nitrogen) | 1 | 5.88% | 14.007 O (oxygen) | 4 | 23.5% | 15.999 S (sulfur) | 1 | 5.88% | 32.06 Multiply N_i by m_i to compute the mass for each element. Then sum those values to compute the molecular mass, m: | number of atoms | atom percent | atomic mass/u | mass/u C (carbon) | 2 | 11.8% | 12.011 | 2 × 12.011 = 24.022 H (hydrogen) | 9 | 52.9% | 1.008 | 9 × 1.008 = 9.072 N (nitrogen) | 1 | 5.88% | 14.007 | 1 × 14.007 = 14.007 O (oxygen) | 4 | 23.5% | 15.999 | 4 × 15.999 = 63.996 S (sulfur) | 1 | 5.88% | 32.06 | 1 × 32.06 = 32.06 m = 24.022 u + 9.072 u + 14.007 u + 63.996 u + 32.06 u = 143.157 u Divide the mass for each element by m to calculate mass fractions. Then use the property that mass fractions must sum to one to check the work: | number of atoms | atom percent | mass fraction C (carbon) | 2 | 11.8% | 24.022/143.157 H (hydrogen) | 9 | 52.9% | 9.072/143.157 N (nitrogen) | 1 | 5.88% | 14.007/143.157 O (oxygen) | 4 | 23.5% | 63.996/143.157 S (sulfur) | 1 | 5.88% | 32.06/143.157 Check: 24.022/143.157 + 9.072/143.157 + 14.007/143.157 + 63.996/143.157 + 32.06/143.157 = 1 Compute mass percents using the mass fractions: Answer: | | | number of atoms | atom percent | mass percent C (carbon) | 2 | 11.8% | 24.022/143.157 × 100% = 16.78% H (hydrogen) | 9 | 52.9% | 9.072/143.157 × 100% = 6.337% N (nitrogen) | 1 | 5.88% | 14.007/143.157 × 100% = 9.784% O (oxygen) | 4 | 23.5% | 63.996/143.157 × 100% = 44.70% S (sulfur) | 1 | 5.88% | 32.06/143.157 × 100% = 22.39%

Mass fraction pie chart