Input interpretation
![rhodamine B | molar mass](../image_source/7e6644780825a6bd3a85a769db48e277.png)
rhodamine B | molar mass
Result
![Find the molar mass, M, for rhodamine B: 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_28H_31N_2O_3Cl Use the chemical formula to count the number of atoms, N_i, for each element: | N_i C (carbon) | 28 Cl (chlorine) | 1 H (hydrogen) | 31 N (nitrogen) | 2 O (oxygen) | 3 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) | 28 | 12.011 Cl (chlorine) | 1 | 35.45 H (hydrogen) | 31 | 1.008 N (nitrogen) | 2 | 14.007 O (oxygen) | 3 | 15.999 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) | 28 | 12.011 | 28 × 12.011 = 336.308 Cl (chlorine) | 1 | 35.45 | 1 × 35.45 = 35.45 H (hydrogen) | 31 | 1.008 | 31 × 1.008 = 31.248 N (nitrogen) | 2 | 14.007 | 2 × 14.007 = 28.014 O (oxygen) | 3 | 15.999 | 3 × 15.999 = 47.997 M = 336.308 g/mol + 35.45 g/mol + 31.248 g/mol + 28.014 g/mol + 47.997 g/mol = 479.02 g/mol](../image_source/beb474a53aa34b8022053c5b167dcb4d.png)
Find the molar mass, M, for rhodamine B: 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_28H_31N_2O_3Cl Use the chemical formula to count the number of atoms, N_i, for each element: | N_i C (carbon) | 28 Cl (chlorine) | 1 H (hydrogen) | 31 N (nitrogen) | 2 O (oxygen) | 3 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) | 28 | 12.011 Cl (chlorine) | 1 | 35.45 H (hydrogen) | 31 | 1.008 N (nitrogen) | 2 | 14.007 O (oxygen) | 3 | 15.999 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) | 28 | 12.011 | 28 × 12.011 = 336.308 Cl (chlorine) | 1 | 35.45 | 1 × 35.45 = 35.45 H (hydrogen) | 31 | 1.008 | 31 × 1.008 = 31.248 N (nitrogen) | 2 | 14.007 | 2 × 14.007 = 28.014 O (oxygen) | 3 | 15.999 | 3 × 15.999 = 47.997 M = 336.308 g/mol + 35.45 g/mol + 31.248 g/mol + 28.014 g/mol + 47.997 g/mol = 479.02 g/mol
Unit conversion
![0.479 kg/mol (kilograms per mole)](../image_source/bb1680ce939f87f75d03fb496ec8a24f.png)
0.479 kg/mol (kilograms per mole)
Comparisons
![≈ 0.66 × molar mass of fullerene ( ≈ 721 g/mol )](../image_source/ac5e65e420f344a84371806cedef7a97.png)
≈ 0.66 × molar mass of fullerene ( ≈ 721 g/mol )
![≈ 2.5 × molar mass of caffeine ( ≈ 194 g/mol )](../image_source/de91635adb452a32b9c2aec5bb2106a7.png)
≈ 2.5 × molar mass of caffeine ( ≈ 194 g/mol )
![≈ 8.2 × molar mass of sodium chloride ( ≈ 58 g/mol )](../image_source/539a2bb5ce7aa9d94b0193226a0fed86.png)
≈ 8.2 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
![Mass of a molecule m from m = M/N_A: | 8×10^-22 grams | 8×10^-25 kg (kilograms) | 479 u (unified atomic mass units) | 479 Da (daltons)](../image_source/2bf1ee0a561511c8289ec0fc23dd6341.png)
Mass of a molecule m from m = M/N_A: | 8×10^-22 grams | 8×10^-25 kg (kilograms) | 479 u (unified atomic mass units) | 479 Da (daltons)
![Relative molecular mass M_r from M_r = M_u/M: | 479](../image_source/c105af51fdd2e578ddfa4b01465976fd.png)
Relative molecular mass M_r from M_r = M_u/M: | 479