Input interpretation
chloropentaammineruthenium(II) chloride | molar mass
Result
Find the molar mass, M, for chloropentaammineruthenium(II) chloride: 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: H_15Cl_2N_5Ru Use the chemical formula to count the number of atoms, N_i, for each element: | N_i Cl (chlorine) | 2 H (hydrogen) | 15 N (nitrogen) | 5 Ru (ruthenium) | 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) Cl (chlorine) | 2 | 35.45 H (hydrogen) | 15 | 1.008 N (nitrogen) | 5 | 14.007 Ru (ruthenium) | 1 | 101.07 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) Cl (chlorine) | 2 | 35.45 | 2 × 35.45 = 70.90 H (hydrogen) | 15 | 1.008 | 15 × 1.008 = 15.120 N (nitrogen) | 5 | 14.007 | 5 × 14.007 = 70.035 Ru (ruthenium) | 1 | 101.07 | 1 × 101.07 = 101.07 M = 70.90 g/mol + 15.120 g/mol + 70.035 g/mol + 101.07 g/mol = 257.13 g/mol
Unit conversion
0.2571 kg/mol (kilograms per mole)
Comparisons
≈ 0.36 × molar mass of fullerene ( ≈ 721 g/mol )
≈ 1.3 × molar mass of caffeine ( ≈ 194 g/mol )
≈ 4.4 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 4.3×10^-22 grams | 4.3×10^-25 kg (kilograms) | 257 u (unified atomic mass units) | 257 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 257