Input interpretation
![mercuric oxide | elemental composition](../image_source/cde5b12cc55ab0ac2a10b53b1533bff0.png)
mercuric oxide | elemental composition
Result
![Find the elemental composition for mercuric oxide 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: HgO 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 Hg (mercury) | 1 O (oxygen) | 1 N_atoms = 1 + 1 = 2 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 Hg (mercury) | 1 | 1/2 O (oxygen) | 1 | 1/2 Check: 1/2 + 1/2 = 1 Compute atom percents using the atom fractions: | number of atoms | atom percent Hg (mercury) | 1 | 1/2 × 100% = 50.0% O (oxygen) | 1 | 1/2 × 100% = 50.0% 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 Hg (mercury) | 1 | 50.0% | 200.592 O (oxygen) | 1 | 50.0% | 15.999 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 Hg (mercury) | 1 | 50.0% | 200.592 | 1 × 200.592 = 200.592 O (oxygen) | 1 | 50.0% | 15.999 | 1 × 15.999 = 15.999 m = 200.592 u + 15.999 u = 216.591 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 Hg (mercury) | 1 | 50.0% | 200.592/216.591 O (oxygen) | 1 | 50.0% | 15.999/216.591 Check: 200.592/216.591 + 15.999/216.591 = 1 Compute mass percents using the mass fractions: Answer: | | | number of atoms | atom percent | mass percent Hg (mercury) | 1 | 50.0% | 200.592/216.591 × 100% = 92.61% O (oxygen) | 1 | 50.0% | 15.999/216.591 × 100% = 7.387%](../image_source/17a18158960c6083d0fceaa591d6ac95.png)
Find the elemental composition for mercuric oxide 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: HgO 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 Hg (mercury) | 1 O (oxygen) | 1 N_atoms = 1 + 1 = 2 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 Hg (mercury) | 1 | 1/2 O (oxygen) | 1 | 1/2 Check: 1/2 + 1/2 = 1 Compute atom percents using the atom fractions: | number of atoms | atom percent Hg (mercury) | 1 | 1/2 × 100% = 50.0% O (oxygen) | 1 | 1/2 × 100% = 50.0% 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 Hg (mercury) | 1 | 50.0% | 200.592 O (oxygen) | 1 | 50.0% | 15.999 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 Hg (mercury) | 1 | 50.0% | 200.592 | 1 × 200.592 = 200.592 O (oxygen) | 1 | 50.0% | 15.999 | 1 × 15.999 = 15.999 m = 200.592 u + 15.999 u = 216.591 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 Hg (mercury) | 1 | 50.0% | 200.592/216.591 O (oxygen) | 1 | 50.0% | 15.999/216.591 Check: 200.592/216.591 + 15.999/216.591 = 1 Compute mass percents using the mass fractions: Answer: | | | number of atoms | atom percent | mass percent Hg (mercury) | 1 | 50.0% | 200.592/216.591 × 100% = 92.61% O (oxygen) | 1 | 50.0% | 15.999/216.591 × 100% = 7.387%
Mass fraction pie chart
![Mass fraction pie chart](../image_source/f2a5c61d09037a99ecf274a35435689d.png)
Mass fraction pie chart