Input interpretation
2-thienyllithium | molar mass
Result
Find the molar mass, M, for 2-thienyllithium: 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_4H_3LiS Use the chemical formula to count the number of atoms, N_i, for each element: | N_i C (carbon) | 4 H (hydrogen) | 3 Li (lithium) | 1 S (sulfur) | 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) C (carbon) | 4 | 12.011 H (hydrogen) | 3 | 1.008 Li (lithium) | 1 | 6.94 S (sulfur) | 1 | 32.06 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) C (carbon) | 4 | 12.011 | 4 × 12.011 = 48.044 H (hydrogen) | 3 | 1.008 | 3 × 1.008 = 3.024 Li (lithium) | 1 | 6.94 | 1 × 6.94 = 6.94 S (sulfur) | 1 | 32.06 | 1 × 32.06 = 32.06 M = 48.044 g/mol + 3.024 g/mol + 6.94 g/mol + 32.06 g/mol = 90.07 g/mol
Unit conversion
0.0901 kg/mol (kilograms per mole)
Comparisons
≈ ( 0.12 ≈ 1/8 ) × molar mass of fullerene ( ≈ 721 g/mol )
≈ 0.46 × molar mass of caffeine ( ≈ 194 g/mol )
≈ 1.5 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
Mass of a molecule m from m = M/N_A: | 1.5×10^-22 grams | 1.5×10^-25 kg (kilograms) | 90 u (unified atomic mass units) | 90 Da (daltons)
Relative molecular mass M_r from M_r = M_u/M: | 90