Input interpretation
thallium(III) oxide | molar mass
Result
Find the molar mass, M, for thallium(III) oxide: 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: Tl_2O_3 Use the chemical formula to count the number of atoms, N_i, for each element: | N_i O (oxygen) | 3 Tl (thallium) | 2 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) O (oxygen) | 3 | 15.999 Tl (thallium) | 2 | 204.38 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) O (oxygen) | 3 | 15.999 | 3 × 15.999 = 47.997 Tl (thallium) | 2 | 204.38 | 2 × 204.38 = 408.76 M = 47.997 g/mol + 408.76 g/mol = 456.76 g/mol
Unit conversion
0.45676 kg/mol (kilograms per mole)
Comparisons
≈ 0.63 × molar mass of fullerene ( ≈ 721 g/mol )
≈ 2.4 × molar mass of caffeine ( ≈ 194 g/mol )
≈ 7.8 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 7.6×10^-22 grams | 7.6×10^-25 kg (kilograms) | 457 u (unified atomic mass units) | 457 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 457