Input interpretation
2, 3, 7, 8, 12, 13, 17, 18-octaethyl-21H, 23 H-porphine copper(II) | relative molecular mass
Result
Find the relative molecular mass, M_r, for 2, 3, 7, 8, 12, 13, 17, 18-octaethyl-21H, 23 H-porphine copper(II): M_r = sum _iN_im_i/m_u 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: (C_36H_46CuN_4)^2+ Use the chemical formula to count the number of atoms, N_i, for each element: | N_i Cu (copper) | 1 C (carbon) | 36 N (nitrogen) | 4 H (hydrogen) | 46 Look up the atomic mass, m_i, in unified atomic mass units, u, for each element in the periodic table. Since m_i is divided by the atomic mass constant, m_u, the result is a unitless relative atomic mass: | N_i | m_i/m_u Cu (copper) | 1 | 63.546 C (carbon) | 36 | 12.011 N (nitrogen) | 4 | 14.007 H (hydrogen) | 46 | 1.008 Multiply N_i by m_i/m_u to compute the relative mass for each element. Then sum those values to compute the relative molecular mass, M_r: Answer: | | | N_i | m_i/m_u | relative mass Cu (copper) | 1 | 63.546 | 1 × 63.546 = 63.546 C (carbon) | 36 | 12.011 | 36 × 12.011 = 432.396 N (nitrogen) | 4 | 14.007 | 4 × 14.007 = 56.028 H (hydrogen) | 46 | 1.008 | 46 × 1.008 = 46.368 M_r = 63.546 + 432.396 + 56.028 + 46.368 = 598.338
Comparisons
≈ 0.83 × relative molecular mass of fullerene ( ≈ 721 )
≈ 3.1 × relative molecular mass of caffeine ( ≈ 194 )
≈ 10 × relative molecular mass of sodium chloride ( ≈ 58 )
Corresponding quantities
Molar mass M from M = M_uM_r: | 598 g/mol (grams per mole)
Molecular mass m from m = M_rM_u/N_A: | 9.9×10^-22 grams | 9.9×10^-25 kg (kilograms)