Input interpretation
potassium nitrite | molecular mass
Result
Find the molecular mass, m, for potassium nitrite: 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: KNO_2 Use the chemical formula to count the number of atoms, N_i, for each element: | N_i K (potassium) | 1 N (nitrogen) | 1 O (oxygen) | 2 Look up the atomic mass, m_i, in unified atomic mass units, u, for each element in the periodic table: | N_i | m_i/u K (potassium) | 1 | 39.0983 N (nitrogen) | 1 | 14.007 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 molecular mass, m: Answer: | | | N_i | m_i/u | mass/u K (potassium) | 1 | 39.0983 | 1 × 39.0983 = 39.0983 N (nitrogen) | 1 | 14.007 | 1 × 14.007 = 14.007 O (oxygen) | 2 | 15.999 | 2 × 15.999 = 31.998 m = 39.0983 u + 14.007 u + 31.998 u = 85.103 u
Unit conversions
85.103 Da (daltons)
0.085103 kDa (kilodaltons)
1.4132×10^-22 grams
1.4132×10^-25 kg (kilograms)
85.107 chemical atomic mass units (unit officially deprecated)
85.13 physical atomic mass units (unit officially deprecated)
Comparisons as mass of molecule
≈ ( 0.12 ≈ 1/8 ) × molecular mass of fullerene ( ≈ 721 u )
≈ 0.44 × molecular mass of caffeine ( ≈ 194 u )
≈ 1.5 × molecular mass of sodium chloride ( ≈ 58 u )
Corresponding quantities
Relative atomic mass A_r from A_r = m_aN_A/M_u: | 85
Molar mass M from M = m_aN_A: | 85 g/mol (grams per mole)
Relative molecular mass M_r from M_r = m_mN_A/M_u: | 85
Molar mass M from M = m_mN_A: | 85 g/mol (grams per mole)