Input interpretation
erbium bromide hexahydrate | molecular mass
Result
Find the molecular mass, m, for erbium bromide hexahydrate: 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: ErBr_3·6H_2O Use the chemical formula, ErBr_3·6H_2O, to count the number of atoms, N_i, for each element: | N_i Br (bromine) | 3 Er (erbium) | 1 H (hydrogen) | 12 O (oxygen) | 6 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 Br (bromine) | 3 | 79.904 Er (erbium) | 1 | 167.259 H (hydrogen) | 12 | 1.008 O (oxygen) | 6 | 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 Br (bromine) | 3 | 79.904 | 3 × 79.904 = 239.712 Er (erbium) | 1 | 167.259 | 1 × 167.259 = 167.259 H (hydrogen) | 12 | 1.008 | 12 × 1.008 = 12.096 O (oxygen) | 6 | 15.999 | 6 × 15.999 = 95.994 m = 239.712 u + 167.259 u + 12.096 u + 95.994 u = 515.061 u
Unit conversions
515.06 Da (daltons)
0.51506 kDa (kilodaltons)
8.5528×10^-22 grams
8.5528×10^-25 kg (kilograms)
515.08 chemical atomic mass units (unit officially deprecated)
515.22 physical atomic mass units (unit officially deprecated)
Comparisons as mass of molecule
≈ 0.71 × molecular mass of fullerene ( ≈ 721 u )
≈ 2.7 × molecular mass of caffeine ( ≈ 194 u )
≈ 8.8 × molecular mass of sodium chloride ( ≈ 58 u )
Corresponding quantities
Relative atomic mass A_r from A_r = m_aN_A/M_u: | 515
Molar mass M from M = m_aN_A: | 515 g/mol (grams per mole)
Relative molecular mass M_r from M_r = m_mN_A/M_u: | 515
Molar mass M from M = m_mN_A: | 515 g/mol (grams per mole)