Input interpretation
ammonium perrhenate | molar mass
Result
Find the molar mass, M, for ammonium perrhenate: 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: NH_4ReO_4 Use the chemical formula to count the number of atoms, N_i, for each element: | N_i H (hydrogen) | 4 N (nitrogen) | 1 O (oxygen) | 4 Re (rhenium) | 1 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) H (hydrogen) | 4 | 1.008 N (nitrogen) | 1 | 14.007 O (oxygen) | 4 | 15.999 Re (rhenium) | 1 | 186.207 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) H (hydrogen) | 4 | 1.008 | 4 × 1.008 = 4.032 N (nitrogen) | 1 | 14.007 | 1 × 14.007 = 14.007 O (oxygen) | 4 | 15.999 | 4 × 15.999 = 63.996 Re (rhenium) | 1 | 186.207 | 1 × 186.207 = 186.207 M = 4.032 g/mol + 14.007 g/mol + 63.996 g/mol + 186.207 g/mol = 268.242 g/mol
Unit conversion
0.26824 kg/mol (kilograms per mole)
Comparisons
≈ 0.37 × molar mass of fullerene ( ≈ 721 g/mol )
≈ 1.4 × molar mass of caffeine ( ≈ 194 g/mol )
≈ 4.6 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 4.5×10^-22 grams | 4.5×10^-25 kg (kilograms) | 268 u (unified atomic mass units) | 268 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 268