Input interpretation
carbon tetrabromide | molar mass
Result
Find the molar mass, M, for carbon tetrabromide: 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: CBr_4 Use the chemical formula, CBr_4, to count the number of atoms, N_i, for each element: | N_i Br (bromine) | 4 C (carbon) | 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) | 4 | 79.904 C (carbon) | 1 | 12.011 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) | 4 | 79.904 | 4 × 79.904 = 319.616 C (carbon) | 1 | 12.011 | 1 × 12.011 = 12.011 M = 319.616 g/mol + 12.011 g/mol = 331.627 g/mol
Unit conversion
0.33163 kg/mol (kilograms per mole)
Comparisons
≈ 0.46 × molar mass of fullerene ( ≈ 721 g/mol )
≈ 1.7 × molar mass of caffeine ( ≈ 194 g/mol )
≈ 5.7 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 5.5×10^-22 grams | 5.5×10^-25 kg (kilograms) | 332 u (unified atomic mass units) | 332 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 332