Input interpretation
sodium phosphotungstate hydrate | molar mass
Result
Find the molar mass, M, for sodium phosphotungstate hydrate: 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_3PO_4·12WO_3·xH_2O Use the chemical formula to count the number of atoms, N_i, for each element: | N_i H (hydrogen) | 5 Na (sodium) | 3 O (oxygen) | 41 P (phosphorus) | 1 W (tungsten) | 12 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) | 5 | 1.008 Na (sodium) | 3 | 22.98976928 O (oxygen) | 41 | 15.999 P (phosphorus) | 1 | 30.973761998 W (tungsten) | 12 | 183.84 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) | 5 | 1.008 | 5 × 1.008 = 5.040 Na (sodium) | 3 | 22.98976928 | 3 × 22.98976928 = 68.96930784 O (oxygen) | 41 | 15.999 | 41 × 15.999 = 655.959 P (phosphorus) | 1 | 30.973761998 | 1 × 30.973761998 = 30.973761998 W (tungsten) | 12 | 183.84 | 12 × 183.84 = 2206.08 M = 5.040 g/mol + 68.96930784 g/mol + 655.959 g/mol + 30.973761998 g/mol + 2206.08 g/mol = 2967.02 g/mol
Unit conversion
2.967 kg/mol (kilograms per mole)
Comparisons
≈ 4.1 × molar mass of fullerene ( ≈ 721 g/mol )
≈ 15 × molar mass of caffeine ( ≈ 194 g/mol )
≈ 51 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 4.9×10^-21 grams | 4.9×10^-24 kg (kilograms) | 2967 u (unified atomic mass units) | 3 kDa (kilodaltons)
Relative molecular mass M_r from M_r = M_u/M: | 2967