Input interpretation
mercury potassium iodide | molar mass
Result
Find the molar mass, M, for mercury potassium iodide: 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: K_2HgI_4 Use the chemical formula to count the number of atoms, N_i, for each element: | N_i Hg (mercury) | 1 I (iodine) | 4 K (potassium) | 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) Hg (mercury) | 1 | 200.592 I (iodine) | 4 | 126.90447 K (potassium) | 2 | 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) Hg (mercury) | 1 | 200.592 | 1 × 200.592 = 200.592 I (iodine) | 4 | 126.90447 | 4 × 126.90447 = 507.61788 K (potassium) | 2 | 39.0983 | 2 × 39.0983 = 78.1966 M = 200.592 g/mol + 507.61788 g/mol + 78.1966 g/mol = 786.406 g/mol
Unit conversion
0.786406 kg/mol (kilograms per mole)
Comparisons
≈ 1.1 × molar mass of fullerene ( ≈ 721 g/mol )
≈ 4 × molar mass of caffeine ( ≈ 194 g/mol )
≈ 13 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 1.3×10^-21 grams | 1.3×10^-24 kg (kilograms) | 786 u (unified atomic mass units) | 786 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 786