Input interpretation
![sodium sulfide | molar mass](../image_source/152fd088f8fe2d48d83664d383219c54.png)
sodium sulfide | molar mass
Result
![Find the molar mass, M, for sodium sulfide: 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: Na_2S Use the chemical formula to count the number of atoms, N_i, for each element: | N_i Na (sodium) | 2 S (sulfur) | 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) Na (sodium) | 2 | 22.98976928 S (sulfur) | 1 | 32.06 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) Na (sodium) | 2 | 22.98976928 | 2 × 22.98976928 = 45.97953856 S (sulfur) | 1 | 32.06 | 1 × 32.06 = 32.06 M = 45.97953856 g/mol + 32.06 g/mol = 78.04 g/mol](../image_source/7999857dd5a191946dec2248c1f27f89.png)
Find the molar mass, M, for sodium sulfide: 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: Na_2S Use the chemical formula to count the number of atoms, N_i, for each element: | N_i Na (sodium) | 2 S (sulfur) | 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) Na (sodium) | 2 | 22.98976928 S (sulfur) | 1 | 32.06 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) Na (sodium) | 2 | 22.98976928 | 2 × 22.98976928 = 45.97953856 S (sulfur) | 1 | 32.06 | 1 × 32.06 = 32.06 M = 45.97953856 g/mol + 32.06 g/mol = 78.04 g/mol
Unit conversion
![0.07804 kg/mol (kilograms per mole)](../image_source/67097d63677c32a1ad24f86dc6d14aae.png)
0.07804 kg/mol (kilograms per mole)
Comparisons
![≈ ( 0.11 ≈ 1/9 ) × molar mass of fullerene ( ≈ 721 g/mol )](../image_source/88944d9cc36b51f899a831a6361b2d89.png)
≈ ( 0.11 ≈ 1/9 ) × molar mass of fullerene ( ≈ 721 g/mol )
![≈ 0.4 × molar mass of caffeine ( ≈ 194 g/mol )](../image_source/05ec35d95feabd9e78edc7bbaefdf22b.png)
≈ 0.4 × molar mass of caffeine ( ≈ 194 g/mol )
![≈ 1.3 × molar mass of sodium chloride ( ≈ 58 g/mol )](../image_source/dd38f9369e2c2300fc0aa2d78aa0901a.png)
≈ 1.3 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
![Mass of a molecule m from m = M/N_A: | 1.3×10^-22 grams | 1.3×10^-25 kg (kilograms) | 78 u (unified atomic mass units) | 78 Da (daltons)](../image_source/b60a85b42a1b228be051c7337cbbdab1.png)
Mass of a molecule m from m = M/N_A: | 1.3×10^-22 grams | 1.3×10^-25 kg (kilograms) | 78 u (unified atomic mass units) | 78 Da (daltons)
![Relative molecular mass M_r from M_r = M_u/M: | 78](../image_source/b76837ac4d8b40ed8f551113166a82a0.png)
Relative molecular mass M_r from M_r = M_u/M: | 78