Input interpretation
manganese dioxide | molar mass
Result
Find the molar mass, M, for manganese dioxide: 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: MnO_2 Use the chemical formula to count the number of atoms, N_i, for each element: | N_i Mn (manganese) | 1 O (oxygen) | 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) Mn (manganese) | 1 | 54.938044 O (oxygen) | 2 | 15.999 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) Mn (manganese) | 1 | 54.938044 | 1 × 54.938044 = 54.938044 O (oxygen) | 2 | 15.999 | 2 × 15.999 = 31.998 M = 54.938044 g/mol + 31.998 g/mol = 86.936 g/mol
Unit conversion
0.086936 kg/mol (kilograms per mole)
Comparisons
≈ ( 0.12 ≈ 1/8 ) × molar mass of fullerene ( ≈ 721 g/mol )
≈ 0.45 × molar mass of caffeine ( ≈ 194 g/mol )
≈ 1.5 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 1.4×10^-22 grams | 1.4×10^-25 kg (kilograms) | 87 u (unified atomic mass units) | 87 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 87