Input interpretation
![L-lysine | relative molecular mass](../image_source/cb935775f016eba246b00db591487725.png)
L-lysine | relative molecular mass
Result
![Find the relative molecular mass, M_r, for L-lysine: 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: H_2N(CH_2)_4CH(NH_2)CO_2H Use the chemical formula to count the number of atoms, N_i, for each element: | N_i C (carbon) | 6 H (hydrogen) | 14 N (nitrogen) | 2 O (oxygen) | 2 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 C (carbon) | 6 | 12.011 H (hydrogen) | 14 | 1.008 N (nitrogen) | 2 | 14.007 O (oxygen) | 2 | 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 C (carbon) | 6 | 12.011 | 6 × 12.011 = 72.066 H (hydrogen) | 14 | 1.008 | 14 × 1.008 = 14.112 N (nitrogen) | 2 | 14.007 | 2 × 14.007 = 28.014 O (oxygen) | 2 | 15.999 | 2 × 15.999 = 31.998 M_r = 72.066 + 14.112 + 28.014 + 31.998 = 146.190](../image_source/3e855c30bd942d5e27daf02cf7f2c6ba.png)
Find the relative molecular mass, M_r, for L-lysine: 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: H_2N(CH_2)_4CH(NH_2)CO_2H Use the chemical formula to count the number of atoms, N_i, for each element: | N_i C (carbon) | 6 H (hydrogen) | 14 N (nitrogen) | 2 O (oxygen) | 2 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 C (carbon) | 6 | 12.011 H (hydrogen) | 14 | 1.008 N (nitrogen) | 2 | 14.007 O (oxygen) | 2 | 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 C (carbon) | 6 | 12.011 | 6 × 12.011 = 72.066 H (hydrogen) | 14 | 1.008 | 14 × 1.008 = 14.112 N (nitrogen) | 2 | 14.007 | 2 × 14.007 = 28.014 O (oxygen) | 2 | 15.999 | 2 × 15.999 = 31.998 M_r = 72.066 + 14.112 + 28.014 + 31.998 = 146.190
Comparisons
![≈ ( 0.2 ≈ 1/5 ) × relative molecular mass of fullerene ( ≈ 721 )](../image_source/d07c4a05bbcf3f0d3cb33c3c100c8a4e.png)
≈ ( 0.2 ≈ 1/5 ) × relative molecular mass of fullerene ( ≈ 721 )
![≈ 0.75 × relative molecular mass of caffeine ( ≈ 194 )](../image_source/a83031e14797feb436b290c5a91d3d8c.png)
≈ 0.75 × relative molecular mass of caffeine ( ≈ 194 )
![≈ 2.5 × relative molecular mass of sodium chloride ( ≈ 58 )](../image_source/e8c9c577062ad7ed6f7591bb8c988fe9.png)
≈ 2.5 × relative molecular mass of sodium chloride ( ≈ 58 )
Corresponding quantities
![Molar mass M from M = M_uM_r: | 146 g/mol (grams per mole)](../image_source/a7ff57b0b952fe7da5199575f13b315f.png)
Molar mass M from M = M_uM_r: | 146 g/mol (grams per mole)
![Molecular mass m from m = M_rM_u/N_A: | 2.4×10^-22 grams | 2.4×10^-25 kg (kilograms)](../image_source/528b7de5400975d781e4b4d469e95f85.png)
Molecular mass m from m = M_rM_u/N_A: | 2.4×10^-22 grams | 2.4×10^-25 kg (kilograms)