Input interpretation
tetraphenylphosphonium bromide | molar mass
Result
Find the molar mass, M, for tetraphenylphosphonium bromide: 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: (C_6H_5)_4P(Br) Use the chemical formula to count the number of atoms, N_i, for each element: | N_i Br (bromine) | 1 C (carbon) | 24 H (hydrogen) | 20 P (phosphorus) | 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) | 1 | 79.904 C (carbon) | 24 | 12.011 H (hydrogen) | 20 | 1.008 P (phosphorus) | 1 | 30.973761998 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) | 1 | 79.904 | 1 × 79.904 = 79.904 C (carbon) | 24 | 12.011 | 24 × 12.011 = 288.264 H (hydrogen) | 20 | 1.008 | 20 × 1.008 = 20.160 P (phosphorus) | 1 | 30.973761998 | 1 × 30.973761998 = 30.973761998 M = 79.904 g/mol + 288.264 g/mol + 20.160 g/mol + 30.973761998 g/mol = 419.302 g/mol
Unit conversion
0.4193 kg/mol (kilograms per mole)
Comparisons
≈ 0.58 × molar mass of fullerene ( ≈ 721 g/mol )
≈ 2.2 × molar mass of caffeine ( ≈ 194 g/mol )
≈ 7.2 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 7×10^-22 grams | 7×10^-25 kg (kilograms) | 419 u (unified atomic mass units) | 419 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 419