Input interpretation
magnesium orthosilicate | molecular mass
Result
Find the molecular mass, m, for magnesium orthosilicate: 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: Mg_2SiO_4 Use the chemical formula, Mg_2SiO_4, to count the number of atoms, N_i, for each element: | N_i Mg (magnesium) | 2 O (oxygen) | 4 Si (silicon) | 1 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 Mg (magnesium) | 2 | 24.305 O (oxygen) | 4 | 15.999 Si (silicon) | 1 | 28.085 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 Mg (magnesium) | 2 | 24.305 | 2 × 24.305 = 48.610 O (oxygen) | 4 | 15.999 | 4 × 15.999 = 63.996 Si (silicon) | 1 | 28.085 | 1 × 28.085 = 28.085 m = 48.610 u + 63.996 u + 28.085 u = 140.691 u
Unit conversions
140.69 Da (daltons)
0.14069 kDa (kilodaltons)
2.3362×10^-22 grams
2.3362×10^-25 kg (kilograms)
140.7 chemical atomic mass units (unit officially deprecated)
140.74 physical atomic mass units (unit officially deprecated)
Comparisons as mass of molecule
≈ ( 0.2 ≈ 1/5 ) × molecular mass of fullerene ( ≈ 721 u )
≈ 0.72 × molecular mass of caffeine ( ≈ 194 u )
≈ 2.4 × molecular mass of sodium chloride ( ≈ 58 u )
Corresponding quantities
Relative atomic mass A_r from A_r = m_aN_A/M_u: | 141
Molar mass M from M = m_aN_A: | 141 g/mol (grams per mole)
Relative molecular mass M_r from M_r = m_mN_A/M_u: | 141
Molar mass M from M = m_mN_A: | 141 g/mol (grams per mole)