Input interpretation
alpha, alpha, 4-tribromoacetophenone | molar mass
Result
Find the molar mass, M, for alpha, alpha, 4-tribromoacetophenone: 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: Br_2CHCOC_6H_4Br Use the chemical formula to count the number of atoms, N_i, for each element: | N_i Br (bromine) | 3 C (carbon) | 8 H (hydrogen) | 5 O (oxygen) | 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 C (carbon) | 8 | 12.011 H (hydrogen) | 5 | 1.008 O (oxygen) | 1 | 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) Br (bromine) | 3 | 79.904 | 3 × 79.904 = 239.712 C (carbon) | 8 | 12.011 | 8 × 12.011 = 96.088 H (hydrogen) | 5 | 1.008 | 5 × 1.008 = 5.040 O (oxygen) | 1 | 15.999 | 1 × 15.999 = 15.999 M = 239.712 g/mol + 96.088 g/mol + 5.040 g/mol + 15.999 g/mol = 356.839 g/mol
Unit conversion
0.35684 kg/mol (kilograms per mole)
Comparisons
≈ 0.5 × molar mass of fullerene ( ≈ 721 g/mol )
≈ 1.8 × molar mass of caffeine ( ≈ 194 g/mol )
≈ 6.1 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 5.9×10^-22 grams | 5.9×10^-25 kg (kilograms) | 357 u (unified atomic mass units) | 357 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 357