Input interpretation
sodium trimetaphosphate | molar mass
Result
Find the molar mass, M, for sodium trimetaphosphate: 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: Na_3O_9P_3 Use the chemical formula, Na_3O_9P_3, to count the number of atoms, N_i, for each element: | N_i Na (sodium) | 3 O (oxygen) | 9 P (phosphorus) | 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) Na (sodium) | 3 | 22.98976928 O (oxygen) | 9 | 15.999 P (phosphorus) | 3 | 30.973761998 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) Na (sodium) | 3 | 22.98976928 | 3 × 22.98976928 = 68.96930784 O (oxygen) | 9 | 15.999 | 9 × 15.999 = 143.991 P (phosphorus) | 3 | 30.973761998 | 3 × 30.973761998 = 92.921285994 M = 68.96930784 g/mol + 143.991 g/mol + 92.921285994 g/mol = 305.882 g/mol
Unit conversion
0.30588 kg/mol (kilograms per mole)
Comparisons
≈ 0.42 × molar mass of fullerene ( ≈ 721 g/mol )
≈ 1.6 × molar mass of caffeine ( ≈ 194 g/mol )
≈ 5.2 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 5.1×10^-22 grams | 5.1×10^-25 kg (kilograms) | 306 u (unified atomic mass units) | 306 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 306