Input interpretation
potassium tetrachloroaluminate | molar mass
Result
Find the molar mass, M, for potassium tetrachloroaluminate: 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: KAlCl_4 Use the chemical formula, KAlCl_4, to count the number of atoms, N_i, for each element: | N_i Al (aluminum) | 1 Cl (chlorine) | 4 K (potassium) | 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) Al (aluminum) | 1 | 26.9815385 Cl (chlorine) | 4 | 35.45 K (potassium) | 1 | 39.0983 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 Cl (chlorine) | 4 | 35.45 | 4 × 35.45 = 141.80 K (potassium) | 1 | 39.0983 | 1 × 39.0983 = 39.0983 M = 26.9815385 g/mol + 141.80 g/mol + 39.0983 g/mol = 207.88 g/mol
Unit conversion
0.2079 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) | 208 u (unified atomic mass units) | 208 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 208