Input interpretation
lithium hypochlorite | relative molecular mass
Result
Find the relative molecular mass, M_r, for lithium hypochlorite: M_r = sum _iN_im_i/m_u 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: ClLiO Use the chemical formula to count the number of atoms, N_i, for each element: | N_i Cl (chlorine) | 1 Li (lithium) | 1 O (oxygen) | 1 Look up the atomic mass, m_i, in unified atomic mass units, u, for each element in the periodic table. Since m_i is divided by the atomic mass constant, m_u, the result is a unitless relative atomic mass: | N_i | m_i/m_u Cl (chlorine) | 1 | 35.45 Li (lithium) | 1 | 6.94 O (oxygen) | 1 | 15.999 Multiply N_i by m_i/m_u to compute the relative mass for each element. Then sum those values to compute the relative molecular mass, M_r: Answer: | | | N_i | m_i/m_u | relative mass Cl (chlorine) | 1 | 35.45 | 1 × 35.45 = 35.45 Li (lithium) | 1 | 6.94 | 1 × 6.94 = 6.94 O (oxygen) | 1 | 15.999 | 1 × 15.999 = 15.999 M_r = 35.45 + 6.94 + 15.999 = 58.39
Comparisons
≈ ( 0.081 ≈ 1/12 ) × relative molecular mass of fullerene ( ≈ 721 )
≈ 0.3 × relative molecular mass of caffeine ( ≈ 194 )
≈ 0.9991 × relative molecular mass of sodium chloride ( ≈ 58.44 )
Corresponding quantities
Molar mass M from M = M_uM_r: | 58 g/mol (grams per mole)
Molecular mass m from m = M_rM_u/N_A: | 9.7×10^-23 grams | 9.7×10^-26 kg (kilograms)