Input interpretation
lead(II) phthalocyanine | molar mass
Result
Find the molar mass, M, for lead(II) phthalocyanine: 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: C_32H_16N_8Pb Use the chemical formula to count the number of atoms, N_i, for each element: | N_i C (carbon) | 32 H (hydrogen) | 16 N (nitrogen) | 8 Pb (lead) | 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) C (carbon) | 32 | 12.011 H (hydrogen) | 16 | 1.008 N (nitrogen) | 8 | 14.007 Pb (lead) | 1 | 207.2 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) C (carbon) | 32 | 12.011 | 32 × 12.011 = 384.352 H (hydrogen) | 16 | 1.008 | 16 × 1.008 = 16.128 N (nitrogen) | 8 | 14.007 | 8 × 14.007 = 112.056 Pb (lead) | 1 | 207.2 | 1 × 207.2 = 207.2 M = 384.352 g/mol + 16.128 g/mol + 112.056 g/mol + 207.2 g/mol = 719.7 g/mol
Unit conversion
0.7197 kg/mol (kilograms per mole)
Comparisons
≈ 0.999 × molar mass of fullerene ( ≈ 720.64 g/mol )
≈ 3.7 × molar mass of caffeine ( ≈ 194 g/mol )
≈ 12 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 1.2×10^-21 grams | 1.2×10^-24 kg (kilograms) | 720 u (unified atomic mass units) | 720 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 720