Input interpretation
praseodymium(III) nitrate pentahydrate | molar mass
Result
Find the molar mass, M, for praseodymium(III) nitrate 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: Pr(NO_3)_3·5H_2O Use the chemical formula to count the number of atoms, N_i, for each element: | N_i H (hydrogen) | 10 N (nitrogen) | 3 O (oxygen) | 14 Pr (praseodymium) | 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) | 10 | 1.008 N (nitrogen) | 3 | 14.007 O (oxygen) | 14 | 15.999 Pr (praseodymium) | 1 | 140.90766 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) | 10 | 1.008 | 10 × 1.008 = 10.080 N (nitrogen) | 3 | 14.007 | 3 × 14.007 = 42.021 O (oxygen) | 14 | 15.999 | 14 × 15.999 = 223.986 Pr (praseodymium) | 1 | 140.90766 | 1 × 140.90766 = 140.90766 M = 10.080 g/mol + 42.021 g/mol + 223.986 g/mol + 140.90766 g/mol = 416.995 g/mol
Unit conversion
0.41699 kg/mol (kilograms per mole)
Comparisons
≈ 0.58 × molar mass of fullerene ( ≈ 721 g/mol )
≈ 2.1 × molar mass of caffeine ( ≈ 194 g/mol )
≈ 7.1 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 6.9×10^-22 grams | 6.9×10^-25 kg (kilograms) | 417 u (unified atomic mass units) | 417 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 417