Input interpretation
aluminum dodecaboride | molar mass
Result
Find the molar mass, M, for aluminum dodecaboride: 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: AlB_12 Use the chemical formula to count the number of atoms, N_i, for each element: | N_i Al (aluminum) | 1 B (boron) | 12 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) Al (aluminum) | 1 | 26.9815385 B (boron) | 12 | 10.81 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) Al (aluminum) | 1 | 26.9815385 | 1 × 26.9815385 = 26.9815385 B (boron) | 12 | 10.81 | 12 × 10.81 = 129.72 M = 26.9815385 g/mol + 129.72 g/mol = 156.70 g/mol
Unit conversion
0.1567 kg/mol (kilograms per mole)
Comparisons
≈ ( 0.22 ≈ 1/5 ) × molar mass of fullerene ( ≈ 721 g/mol )
≈ 0.81 × molar mass of caffeine ( ≈ 194 g/mol )
≈ 2.7 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 2.6×10^-22 grams | 2.6×10^-25 kg (kilograms) | 157 u (unified atomic mass units) | 157 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 157