Input interpretation
antimony pentoxide | molecular mass
Result
Find the molecular mass, m, for antimony pentoxide: 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: Sb_2O_5 Use the chemical formula to count the number of atoms, N_i, for each element: | N_i O (oxygen) | 5 Sb (antimony) | 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 O (oxygen) | 5 | 15.999 Sb (antimony) | 2 | 121.760 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 O (oxygen) | 5 | 15.999 | 5 × 15.999 = 79.995 Sb (antimony) | 2 | 121.760 | 2 × 121.760 = 243.520 m = 79.995 u + 243.520 u = 323.515 u
Unit conversions
323.51 Da (daltons)
0.32351 kDa (kilodaltons)
5.3721×10^-22 grams
5.3721×10^-25 kg (kilograms)
323.53 chemical atomic mass units (unit officially deprecated)
323.62 physical atomic mass units (unit officially deprecated)
Comparisons as mass of molecule
≈ 0.45 × molecular mass of fullerene ( ≈ 721 u )
≈ 1.7 × molecular mass of caffeine ( ≈ 194 u )
≈ 5.5 × molecular mass of sodium chloride ( ≈ 58 u )
Corresponding quantities
Relative atomic mass A_r from A_r = m_aN_A/M_u: | 324
Molar mass M from M = m_aN_A: | 324 g/mol (grams per mole)
Relative molecular mass M_r from M_r = m_mN_A/M_u: | 324
Molar mass M from M = m_mN_A: | 324 g/mol (grams per mole)