Input interpretation
![oxygen | molar mass](../image_source/961f5ae254900488830184dcb9f2783f.png)
oxygen | molar mass
Result
![Find the molar mass, M, for oxygen: 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: O_2 Use the chemical formula to count the number of atoms, N_i, for each element: | N_i 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) 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) O (oxygen) | 2 | 15.999 | 2 × 15.999 = 31.998 M = 31.998 g/mol](../image_source/a358edf389dfa3d541013f075c075ba4.png)
Find the molar mass, M, for oxygen: 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: O_2 Use the chemical formula to count the number of atoms, N_i, for each element: | N_i 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) 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) O (oxygen) | 2 | 15.999 | 2 × 15.999 = 31.998 M = 31.998 g/mol
Unit conversion
![0.031998 kg/mol (kilograms per mole)](../image_source/b1d9621e1faa5dfeb46f224e793dcded.png)
0.031998 kg/mol (kilograms per mole)
Comparisons
![≈ ( 0.16 ≈ 1/6 ) × molar mass of caffeine ( ≈ 194 g/mol )](../image_source/12b8f5034c5b7f0e4682b564d4e60fa3.png)
≈ ( 0.16 ≈ 1/6 ) × molar mass of caffeine ( ≈ 194 g/mol )
![≈ 0.55 × molar mass of sodium chloride ( ≈ 58 g/mol )](../image_source/5fd40077009d718635db539fa3748717.png)
≈ 0.55 × molar mass of sodium chloride ( ≈ 58 g/mol )
![≈ 1.8 × molar mass of water ( ≈ 18 g/mol )](../image_source/77f3596ec3bf0197a1b01c29c8d8c439.png)
≈ 1.8 × molar mass of water ( ≈ 18 g/mol )
Corresponding quantities
![Mass of a molecule m from m = M/N_A: | 5.3×10^-23 grams | 5.3×10^-26 kg (kilograms) | 32 u (unified atomic mass units) | 32 Da (daltons)](../image_source/a159353bed39d7029634402fd0762ebb.png)
Mass of a molecule m from m = M/N_A: | 5.3×10^-23 grams | 5.3×10^-26 kg (kilograms) | 32 u (unified atomic mass units) | 32 Da (daltons)
![Relative molecular mass M_r from M_r = M_u/M: | 32](../image_source/04703f4085a8fe0aa2ce0d72d032d2ce.png)
Relative molecular mass M_r from M_r = M_u/M: | 32