Input interpretation
![cesium perchlorate | relative molecular mass](../image_source/a0a3f4ff647070fe313636feeb34b2d2.png)
cesium perchlorate | relative molecular mass
Result
![Find the relative molecular mass, M_r, for cesium perchlorate: 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: CsClO_4 Use the chemical formula, CsClO_4, to count the number of atoms, N_i, for each element: | N_i Cl (chlorine) | 1 Cs (cesium) | 1 O (oxygen) | 4 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 Cs (cesium) | 1 | 132.90545196 O (oxygen) | 4 | 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 Cs (cesium) | 1 | 132.90545196 | 1 × 132.90545196 = 132.90545196 O (oxygen) | 4 | 15.999 | 4 × 15.999 = 63.996 M_r = 35.45 + 132.90545196 + 63.996 = 232.35](../image_source/108a276d70c66be0a6e2439f44fc8902.png)
Find the relative molecular mass, M_r, for cesium perchlorate: 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: CsClO_4 Use the chemical formula, CsClO_4, to count the number of atoms, N_i, for each element: | N_i Cl (chlorine) | 1 Cs (cesium) | 1 O (oxygen) | 4 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 Cs (cesium) | 1 | 132.90545196 O (oxygen) | 4 | 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 Cs (cesium) | 1 | 132.90545196 | 1 × 132.90545196 = 132.90545196 O (oxygen) | 4 | 15.999 | 4 × 15.999 = 63.996 M_r = 35.45 + 132.90545196 + 63.996 = 232.35
Comparisons
![≈ 0.32 × relative molecular mass of fullerene ( ≈ 721 )](../image_source/cae9ed64ea2b43517a13231e463623a0.png)
≈ 0.32 × relative molecular mass of fullerene ( ≈ 721 )
![≈ 1.2 × relative molecular mass of caffeine ( ≈ 194 )](../image_source/cae914eb760c533ec77fc41fb25d2682.png)
≈ 1.2 × relative molecular mass of caffeine ( ≈ 194 )
![≈ 4 × relative molecular mass of sodium chloride ( ≈ 58 )](../image_source/e76a57e5451a9ea702a16e938f049d11.png)
≈ 4 × relative molecular mass of sodium chloride ( ≈ 58 )
Corresponding quantities
![Molar mass M from M = M_uM_r: | 232 g/mol (grams per mole)](../image_source/7cfacbc736888a8c635bc4060a80f82f.png)
Molar mass M from M = M_uM_r: | 232 g/mol (grams per mole)
![Molecular mass m from m = M_rM_u/N_A: | 3.9×10^-22 grams | 3.9×10^-25 kg (kilograms)](../image_source/14251a61525315b216cf97dfa0907d4a.png)
Molecular mass m from m = M_rM_u/N_A: | 3.9×10^-22 grams | 3.9×10^-25 kg (kilograms)