Input interpretation
magnesium orthosilicate | molar mass
Result
Find the molar 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 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 g·mol^(-1) for each element in the periodic table: | N_i | m_i/g·mol^(-1) 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 molar mass, M: Answer: | | | N_i | m_i/g·mol^(-1) | mass/g·mol^(-1) 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 g/mol + 63.996 g/mol + 28.085 g/mol = 140.691 g/mol
Unit conversion
0.14069 kg/mol (kilograms per mole)
Comparisons
≈ ( 0.2 ≈ 1/5 ) × molar mass of fullerene ( ≈ 721 g/mol )
≈ 0.72 × molar mass of caffeine ( ≈ 194 g/mol )
≈ 2.4 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 2.3×10^-22 grams | 2.3×10^-25 kg (kilograms) | 141 u (unified atomic mass units) | 141 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 141