Input interpretation
![aluminum tribromide | molar mass](../image_source/f879773b8c33d139de00236f1c64f17d.png)
aluminum tribromide | molar mass
Result
![Find the molar mass, M, for aluminum tribromide: 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: AlBr_3 Use the chemical formula to count the number of atoms, N_i, for each element: | N_i Al (aluminum) | 1 Br (bromine) | 3 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) Al (aluminum) | 1 | 26.9815385 Br (bromine) | 3 | 79.904 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) Al (aluminum) | 1 | 26.9815385 | 1 × 26.9815385 = 26.9815385 Br (bromine) | 3 | 79.904 | 3 × 79.904 = 239.712 M = 26.9815385 g/mol + 239.712 g/mol = 266.694 g/mol](../image_source/09294ddb033a0eca820c79b859b8a609.png)
Find the molar mass, M, for aluminum tribromide: 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: AlBr_3 Use the chemical formula to count the number of atoms, N_i, for each element: | N_i Al (aluminum) | 1 Br (bromine) | 3 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) Al (aluminum) | 1 | 26.9815385 Br (bromine) | 3 | 79.904 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) Al (aluminum) | 1 | 26.9815385 | 1 × 26.9815385 = 26.9815385 Br (bromine) | 3 | 79.904 | 3 × 79.904 = 239.712 M = 26.9815385 g/mol + 239.712 g/mol = 266.694 g/mol
Unit conversion
![0.26669 kg/mol (kilograms per mole)](../image_source/df5b98f3dcf0aaf145248ee562005b56.png)
0.26669 kg/mol (kilograms per mole)
Comparisons
![≈ 0.37 × molar mass of fullerene ( ≈ 721 g/mol )](../image_source/415e9f7bc763ab9e850aaa82bb08ad5b.png)
≈ 0.37 × molar mass of fullerene ( ≈ 721 g/mol )
![≈ 1.4 × molar mass of caffeine ( ≈ 194 g/mol )](../image_source/6712278ce7921ef977e621e524bb0a07.png)
≈ 1.4 × molar mass of caffeine ( ≈ 194 g/mol )
![≈ 4.6 × molar mass of sodium chloride ( ≈ 58 g/mol )](../image_source/a195c0619cf2a41fcb65ae4b3881ee56.png)
≈ 4.6 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
![Mass of a molecule m from m = M/N_A: | 4.4×10^-22 grams | 4.4×10^-25 kg (kilograms) | 267 u (unified atomic mass units) | 267 Da (daltons)](../image_source/ba9b56c743837e2418a6758a71f550de.png)
Mass of a molecule m from m = M/N_A: | 4.4×10^-22 grams | 4.4×10^-25 kg (kilograms) | 267 u (unified atomic mass units) | 267 Da (daltons)
![Relative molecular mass M_r from M_r = M_u/M: | 267](../image_source/ba7e982fd3daab35bc01dfd5a6542d4d.png)
Relative molecular mass M_r from M_r = M_u/M: | 267