Input interpretation
hexamethylmelamine | molar mass
Result
Find the molar mass, M, for hexamethylmelamine: 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_9H_18N_6 Use the chemical formula to count the number of atoms, N_i, for each element: | number of atoms C (carbon) | 9 H (hydrogen) | 18 N (nitrogen) | 6 Look up the atomic mass, m_i, in g·mol^(-1) for each element in the periodic table: | number of atoms | atomic mass/g·mol^(-1) C (carbon) | 9 | 12.011 H (hydrogen) | 18 | 1.008 N (nitrogen) | 6 | 14.007 Multiply N_i by m_i to compute the mass for each element. Then sum those values to compute the molar mass, M: Answer: | | | number of atoms | atomic mass/g·mol^(-1) | mass/g·mol^(-1) C (carbon) | 9 | 12.011 | 9 × 12.011 = 108.099 H (hydrogen) | 18 | 1.008 | 18 × 1.008 = 18.144 N (nitrogen) | 6 | 14.007 | 6 × 14.007 = 84.042 M = 108.099 g/mol + 18.144 g/mol + 84.042 g/mol = 210.285 g/mol
Unit conversion
0.21029 kg/mol (kilograms per mole)
Comparisons
≈ 0.29 × molar mass of fullerene (≈ 721 g/mol )
≈ 1.1 × molar mass of caffeine (≈ 194 g/mol )
≈ 3.6 × molar mass of sodium chloride (≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 3.5×10^-22 grams | 3.5×10^-25 kg (kilograms) | 210 u (unified atomic mass units) | 210 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 210