Input interpretation
![cobalt(II) iodide dihydrate | molar mass](../image_source/e1b853cb67bca6265ceac75ab856d91b.png)
cobalt(II) iodide dihydrate | molar mass
Result
![Find the molar mass, M, for cobalt(II) iodide dihydrate: 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: CoI_2·2H_2O Use the chemical formula, CoI_2·2H_2O, to count the number of atoms, N_i, for each element: | N_i Co (cobalt) | 1 H (hydrogen) | 4 I (iodine) | 2 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) Co (cobalt) | 1 | 58.933194 H (hydrogen) | 4 | 1.008 I (iodine) | 2 | 126.90447 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) Co (cobalt) | 1 | 58.933194 | 1 × 58.933194 = 58.933194 H (hydrogen) | 4 | 1.008 | 4 × 1.008 = 4.032 I (iodine) | 2 | 126.90447 | 2 × 126.90447 = 253.80894 O (oxygen) | 2 | 15.999 | 2 × 15.999 = 31.998 M = 58.933194 g/mol + 4.032 g/mol + 253.80894 g/mol + 31.998 g/mol = 348.772 g/mol](../image_source/b229fc5185907ae2698640d69a5f4d86.png)
Find the molar mass, M, for cobalt(II) iodide dihydrate: 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: CoI_2·2H_2O Use the chemical formula, CoI_2·2H_2O, to count the number of atoms, N_i, for each element: | N_i Co (cobalt) | 1 H (hydrogen) | 4 I (iodine) | 2 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) Co (cobalt) | 1 | 58.933194 H (hydrogen) | 4 | 1.008 I (iodine) | 2 | 126.90447 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) Co (cobalt) | 1 | 58.933194 | 1 × 58.933194 = 58.933194 H (hydrogen) | 4 | 1.008 | 4 × 1.008 = 4.032 I (iodine) | 2 | 126.90447 | 2 × 126.90447 = 253.80894 O (oxygen) | 2 | 15.999 | 2 × 15.999 = 31.998 M = 58.933194 g/mol + 4.032 g/mol + 253.80894 g/mol + 31.998 g/mol = 348.772 g/mol
Unit conversion
![0.348772 kg/mol (kilograms per mole)](../image_source/5e7a56e0e4bfb6662b359fa8d5189525.png)
0.348772 kg/mol (kilograms per mole)
Comparisons
![≈ 0.48 × molar mass of fullerene ( ≈ 721 g/mol )](../image_source/1086d3d86831aa0e49954478b0c3965f.png)
≈ 0.48 × molar mass of fullerene ( ≈ 721 g/mol )
![≈ 1.8 × molar mass of caffeine ( ≈ 194 g/mol )](../image_source/fea2a63fe09474d27f1d207979be24fa.png)
≈ 1.8 × molar mass of caffeine ( ≈ 194 g/mol )
![≈ 6 × molar mass of sodium chloride ( ≈ 58 g/mol )](../image_source/2ae64b9b93056af36976a4b394249b56.png)
≈ 6 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
![Mass of a molecule m from m = M/N_A: | 5.8×10^-22 grams | 5.8×10^-25 kg (kilograms) | 349 u (unified atomic mass units) | 349 Da (daltons)](../image_source/e49db1ac4c1d67ee1d0bbfac87f99ba3.png)
Mass of a molecule m from m = M/N_A: | 5.8×10^-22 grams | 5.8×10^-25 kg (kilograms) | 349 u (unified atomic mass units) | 349 Da (daltons)
![Relative molecular mass M_r from M_r = M_u/M: | 349](../image_source/38a3b7c1797e0d4396f12409a7b6d7ee.png)
Relative molecular mass M_r from M_r = M_u/M: | 349