Input interpretation
potassium selenocyanate | molar mass
Result
Find the molar mass, M, for potassium selenocyanate: 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: KSeCN Use the chemical formula to count the number of atoms, N_i, for each element: | N_i C (carbon) | 1 K (potassium) | 1 N (nitrogen) | 1 Se (selenium) | 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) C (carbon) | 1 | 12.011 K (potassium) | 1 | 39.0983 N (nitrogen) | 1 | 14.007 Se (selenium) | 1 | 78.971 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) | 1 | 12.011 | 1 × 12.011 = 12.011 K (potassium) | 1 | 39.0983 | 1 × 39.0983 = 39.0983 N (nitrogen) | 1 | 14.007 | 1 × 14.007 = 14.007 Se (selenium) | 1 | 78.971 | 1 × 78.971 = 78.971 M = 12.011 g/mol + 39.0983 g/mol + 14.007 g/mol + 78.971 g/mol = 144.087 g/mol
Unit conversion
0.14409 kg/mol (kilograms per mole)
Comparisons
≈ ( 0.2 ≈ 1/5 ) × molar mass of fullerene ( ≈ 721 g/mol )
≈ 0.74 × molar mass of caffeine ( ≈ 194 g/mol )
≈ 2.5 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 2.4×10^-22 grams | 2.4×10^-25 kg (kilograms) | 144 u (unified atomic mass units) | 144 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 144