Input interpretation
praseodymium(III) nitrate, hexahydrate | molar mass
Result
Find the molar mass, M, for praseodymium(III) nitrate, hexahydrate: 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)_3·6H_2O Use the chemical formula to count the number of atoms, N_i, for each element: | N_i H (hydrogen) | 2 N (nitrogen) | 3 O (oxygen) | 10 Pr (praseodymium) | 2 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) | 2 | 1.008 N (nitrogen) | 3 | 14.007 O (oxygen) | 10 | 15.999 Pr (praseodymium) | 2 | 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) | 2 | 1.008 | 2 × 1.008 = 2.016 N (nitrogen) | 3 | 14.007 | 3 × 14.007 = 42.021 O (oxygen) | 10 | 15.999 | 10 × 15.999 = 159.990 Pr (praseodymium) | 2 | 140.90766 | 2 × 140.90766 = 281.81532 M = 2.016 g/mol + 42.021 g/mol + 159.990 g/mol + 281.81532 g/mol = 485.842 g/mol
Unit conversion
0.48584 kg/mol (kilograms per mole)
Comparisons
≈ 0.67 × molar mass of fullerene ( ≈ 721 g/mol )
≈ 2.5 × molar mass of caffeine ( ≈ 194 g/mol )
≈ 8.3 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 8.1×10^-22 grams | 8.1×10^-25 kg (kilograms) | 486 u (unified atomic mass units) | 486 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 486