Input interpretation
![scandium tribromide | molar mass](../image_source/a735e4c8c3aa4df5fb6fb6b969c1b307.png)
scandium tribromide | molar mass
Result
![Find the molar mass, M, for scandium 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: ScBr_3 Use the chemical formula, ScBr_3, to count the number of atoms, N_i, for each element: | N_i Br (bromine) | 3 Sc (scandium) | 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) Br (bromine) | 3 | 79.904 Sc (scandium) | 1 | 44.955908 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) Br (bromine) | 3 | 79.904 | 3 × 79.904 = 239.712 Sc (scandium) | 1 | 44.955908 | 1 × 44.955908 = 44.955908 M = 239.712 g/mol + 44.955908 g/mol = 284.668 g/mol](../image_source/5d9401f3eea88d8590dd9bf6443d68ba.png)
Find the molar mass, M, for scandium 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: ScBr_3 Use the chemical formula, ScBr_3, to count the number of atoms, N_i, for each element: | N_i Br (bromine) | 3 Sc (scandium) | 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) Br (bromine) | 3 | 79.904 Sc (scandium) | 1 | 44.955908 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) Br (bromine) | 3 | 79.904 | 3 × 79.904 = 239.712 Sc (scandium) | 1 | 44.955908 | 1 × 44.955908 = 44.955908 M = 239.712 g/mol + 44.955908 g/mol = 284.668 g/mol
Unit conversion
![0.28467 kg/mol (kilograms per mole)](../image_source/1c19c97caf8ee9bf35552ddf0567c619.png)
0.28467 kg/mol (kilograms per mole)
Comparisons
![≈ 0.4 × molar mass of fullerene ( ≈ 721 g/mol )](../image_source/02c0f4d6762a5e2b17471c597b58daed.png)
≈ 0.4 × molar mass of fullerene ( ≈ 721 g/mol )
![≈ 1.5 × molar mass of caffeine ( ≈ 194 g/mol )](../image_source/36080c45fc939d346978ba6123d4d379.png)
≈ 1.5 × molar mass of caffeine ( ≈ 194 g/mol )
![≈ 4.9 × molar mass of sodium chloride ( ≈ 58 g/mol )](../image_source/9218eaff96392e34338b71c67495de33.png)
≈ 4.9 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
![Mass of a molecule m from m = M/N_A: | 4.7×10^-22 grams | 4.7×10^-25 kg (kilograms) | 285 u (unified atomic mass units) | 285 Da (daltons)](../image_source/78ed27a84873c9a7350efc8128a9bee2.png)
Mass of a molecule m from m = M/N_A: | 4.7×10^-22 grams | 4.7×10^-25 kg (kilograms) | 285 u (unified atomic mass units) | 285 Da (daltons)
![Relative molecular mass M_r from M_r = M_u/M: | 285](../image_source/f6a6dc0ad7081c0f3744e2d008943a44.png)
Relative molecular mass M_r from M_r = M_u/M: | 285