Input interpretation
pirenzepine | molar mass
Result
Find the molar mass, M, for pirenzepine: 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_19H_21N_5O_2 Use the chemical formula to count the number of atoms, N_i, for each element: | N_i C (carbon) | 19 H (hydrogen) | 21 N (nitrogen) | 5 O (oxygen) | 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) C (carbon) | 19 | 12.011 H (hydrogen) | 21 | 1.008 N (nitrogen) | 5 | 14.007 O (oxygen) | 2 | 15.999 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) | 19 | 12.011 | 19 × 12.011 = 228.209 H (hydrogen) | 21 | 1.008 | 21 × 1.008 = 21.168 N (nitrogen) | 5 | 14.007 | 5 × 14.007 = 70.035 O (oxygen) | 2 | 15.999 | 2 × 15.999 = 31.998 M = 228.209 g/mol + 21.168 g/mol + 70.035 g/mol + 31.998 g/mol = 351.410 g/mol
Unit conversion
0.35141 kg/mol (kilograms per mole)
Comparisons
≈ 0.49 × molar mass of fullerene ( ≈ 721 g/mol )
≈ 1.8 × molar mass of caffeine ( ≈ 194 g/mol )
≈ 6 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 5.8×10^-22 grams | 5.8×10^-25 kg (kilograms) | 351 u (unified atomic mass units) | 351 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 351