Input interpretation
scandium(III) sulfate pentahydrate | molar mass
Result
Find the molar mass, M, for scandium(III) sulfate pentahydrate: 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: Sc_2(SO_4)_3·5H_2O Use the chemical formula to count the number of atoms, N_i, for each element: | N_i H (hydrogen) | 4 O (oxygen) | 5 S (sulfur) | 1 Sc (scandium) | 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 O (oxygen) | 5 | 15.999 S (sulfur) | 1 | 32.06 Sc (scandium) | 1 | 44.955908 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 O (oxygen) | 5 | 15.999 | 5 × 15.999 = 79.995 S (sulfur) | 1 | 32.06 | 1 × 32.06 = 32.06 Sc (scandium) | 1 | 44.955908 | 1 × 44.955908 = 44.955908 M = 4.032 g/mol + 79.995 g/mol + 32.06 g/mol + 44.955908 g/mol = 161.04 g/mol
Unit conversion
0.16104 kg/mol (kilograms per mole)
Comparisons
≈ ( 0.22 ≈ 1/4 ) × molar mass of fullerene ( ≈ 721 g/mol )
≈ 0.83 × molar mass of caffeine ( ≈ 194 g/mol )
≈ 2.8 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 2.7×10^-22 grams | 2.7×10^-25 kg (kilograms) | 161 u (unified atomic mass units) | 161 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 161