Input interpretation
![strontium hydroxide octahydrate | molar mass](../image_source/f3a1054052adf30e118e55706b4abdc0.png)
strontium hydroxide octahydrate | molar mass
Result
![Find the molar mass, M, for strontium hydroxide octahydrate: 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: Sr(OH)_2·8H_2O Use the chemical formula to count the number of atoms, N_i, for each element: | N_i H (hydrogen) | 4 O (oxygen) | 3 Sr (strontium) | 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) H (hydrogen) | 4 | 1.008 O (oxygen) | 3 | 15.999 Sr (strontium) | 1 | 87.62 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) H (hydrogen) | 4 | 1.008 | 4 × 1.008 = 4.032 O (oxygen) | 3 | 15.999 | 3 × 15.999 = 47.997 Sr (strontium) | 1 | 87.62 | 1 × 87.62 = 87.62 M = 4.032 g/mol + 47.997 g/mol + 87.62 g/mol = 139.65 g/mol](../image_source/e316210dfd51d58059a41701f41ec745.png)
Find the molar mass, M, for strontium hydroxide octahydrate: 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: Sr(OH)_2·8H_2O Use the chemical formula to count the number of atoms, N_i, for each element: | N_i H (hydrogen) | 4 O (oxygen) | 3 Sr (strontium) | 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) H (hydrogen) | 4 | 1.008 O (oxygen) | 3 | 15.999 Sr (strontium) | 1 | 87.62 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) H (hydrogen) | 4 | 1.008 | 4 × 1.008 = 4.032 O (oxygen) | 3 | 15.999 | 3 × 15.999 = 47.997 Sr (strontium) | 1 | 87.62 | 1 × 87.62 = 87.62 M = 4.032 g/mol + 47.997 g/mol + 87.62 g/mol = 139.65 g/mol
Unit conversion
![0.1396 kg/mol (kilograms per mole)](../image_source/d12fb02861b4fe92d08d0268159e10eb.png)
0.1396 kg/mol (kilograms per mole)
Comparisons
![≈ ( 0.19 ≈ 1/5 ) × molar mass of fullerene ( ≈ 721 g/mol )](../image_source/88499a554a0b6fe72e2bc2851eb26ea8.png)
≈ ( 0.19 ≈ 1/5 ) × molar mass of fullerene ( ≈ 721 g/mol )
![≈ 0.72 × molar mass of caffeine ( ≈ 194 g/mol )](../image_source/cd6b64a2011d21c2f74128e3da0b6f7b.png)
≈ 0.72 × molar mass of caffeine ( ≈ 194 g/mol )
![≈ 2.4 × molar mass of sodium chloride ( ≈ 58 g/mol )](../image_source/b2dbf3d2d0bb89fb17cbb572aedee235.png)
≈ 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) | 140 u (unified atomic mass units) | 140 Da (daltons)](../image_source/ae8905fa70271234270692c26559f653.png)
Mass of a molecule m from m = M/N_A: | 2.3×10^-22 grams | 2.3×10^-25 kg (kilograms) | 140 u (unified atomic mass units) | 140 Da (daltons)
![Relative molecular mass M_r from M_r = M_u/M: | 140](../image_source/9c425460b172f4ad04ba1c72cf5dbe59.png)
Relative molecular mass M_r from M_r = M_u/M: | 140