Input interpretation
4-nitrophenol | molar mass
Result
Find the molar mass, M, for 4-nitrophenol: M = sum _iN_im_i Plan: • Write the chemical formula and gather atomic masses from the periodic table. • Determine values for N_i and m_i using these items. • Finally, compute the mass. Write the chemical formula: O_2NC_6H_4OH Use the chemical formula to count the number of atoms, N_i, for each element: | N_i C (carbon) | 6 H (hydrogen) | 5 N (nitrogen) | 1 O (oxygen) | 3 Look up the atomic mass, m_i, in g·mol^(-1) for each element in the periodic table: | N_i | m_i/g·mol^(-1) C (carbon) | 6 | 12.011 H (hydrogen) | 5 | 1.008 N (nitrogen) | 1 | 14.007 O (oxygen) | 3 | 15.999 Multiply N_i by m_i to compute the mass for each element. Then sum those values to compute the molar mass, M: Answer: | | | N_i | m_i/g·mol^(-1) | mass/g·mol^(-1) C (carbon) | 6 | 12.011 | 6 × 12.011 = 72.066 H (hydrogen) | 5 | 1.008 | 5 × 1.008 = 5.040 N (nitrogen) | 1 | 14.007 | 1 × 14.007 = 14.007 O (oxygen) | 3 | 15.999 | 3 × 15.999 = 47.997 M = 72.066 g/mol + 5.040 g/mol + 14.007 g/mol + 47.997 g/mol = 139.110 g/mol
Unit conversion
0.13911 kg/mol (kilograms per mole)
Comparisons
≈ ( 0.19 ≈ 1/5 ) × molar mass of fullerene ( ≈ 721 g/mol )
≈ 0.72 × molar mass of caffeine ( ≈ 194 g/mol )
≈ 2.4 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 2.3×10^-22 grams | 2.3×10^-25 kg (kilograms) | 139 u (unified atomic mass units) | 139 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 139