Input interpretation
sodium sulfate heptahydrate | molar mass
Result
Find the molar mass, M, for sodium sulfate heptahydrate: 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_2SO_4·7H_2O Use the chemical formula, Na_2SO_4·7H_2O, to count the number of atoms, N_i, for each element: | N_i H (hydrogen) | 14 Na (sodium) | 2 O (oxygen) | 11 S (sulfur) | 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) | 14 | 1.008 Na (sodium) | 2 | 22.98976928 O (oxygen) | 11 | 15.999 S (sulfur) | 1 | 32.06 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) | 14 | 1.008 | 14 × 1.008 = 14.112 Na (sodium) | 2 | 22.98976928 | 2 × 22.98976928 = 45.97953856 O (oxygen) | 11 | 15.999 | 11 × 15.999 = 175.989 S (sulfur) | 1 | 32.06 | 1 × 32.06 = 32.06 M = 14.112 g/mol + 45.97953856 g/mol + 175.989 g/mol + 32.06 g/mol = 268.14 g/mol
Unit conversion
0.26814 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