Input interpretation
ferric nitrate | molar mass
Result
Find the molar mass, M, for ferric nitrate: 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: Fe(NO_3)_3 Use the chemical formula to count the number of atoms, N_i, for each element: | N_i Fe (iron) | 1 N (nitrogen) | 3 O (oxygen) | 9 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) Fe (iron) | 1 | 55.845 N (nitrogen) | 3 | 14.007 O (oxygen) | 9 | 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) Fe (iron) | 1 | 55.845 | 1 × 55.845 = 55.845 N (nitrogen) | 3 | 14.007 | 3 × 14.007 = 42.021 O (oxygen) | 9 | 15.999 | 9 × 15.999 = 143.991 M = 55.845 g/mol + 42.021 g/mol + 143.991 g/mol = 241.857 g/mol
Unit conversion
0.24186 kg/mol (kilograms per mole)
Comparisons
≈ 0.34 × molar mass of fullerene ( ≈ 721 g/mol )
≈ 1.2 × molar mass of caffeine ( ≈ 194 g/mol )
≈ 4.1 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 4×10^-22 grams | 4×10^-25 kg (kilograms) | 242 u (unified atomic mass units) | 242 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 242