Input interpretation
potassium fluoride dihydrate | molar mass
Result
Find the molar mass, M, for potassium fluoride dihydrate: 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: FH_4KO_2 Use the chemical formula to count the number of atoms, N_i, for each element: | N_i F (fluorine) | 1 H (hydrogen) | 4 K (potassium) | 1 O (oxygen) | 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) F (fluorine) | 1 | 18.998403163 H (hydrogen) | 4 | 1.008 K (potassium) | 1 | 39.0983 O (oxygen) | 2 | 15.999 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) F (fluorine) | 1 | 18.998403163 | 1 × 18.998403163 = 18.998403163 H (hydrogen) | 4 | 1.008 | 4 × 1.008 = 4.032 K (potassium) | 1 | 39.0983 | 1 × 39.0983 = 39.0983 O (oxygen) | 2 | 15.999 | 2 × 15.999 = 31.998 M = 18.998403163 g/mol + 4.032 g/mol + 39.0983 g/mol + 31.998 g/mol = 94.127 g/mol
Unit conversion
0.094127 kg/mol (kilograms per mole)
Comparisons
≈ ( 0.13 ≈ 1/8 ) × molar mass of fullerene ( ≈ 721 g/mol )
≈ 0.48 × molar mass of caffeine ( ≈ 194 g/mol )
≈ 1.6 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 1.6×10^-22 grams | 1.6×10^-25 kg (kilograms) | 94 u (unified atomic mass units) | 94 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 94