Input interpretation
![perrhenic acid | molar mass](../image_source/1ab7452c7e7fc5108626e2f6f08634fb.png)
perrhenic acid | molar mass
Result
![Find the molar mass, M, for perrhenic acid: 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: HReO_4 Use the chemical formula to count the number of atoms, N_i, for each element: | N_i H (hydrogen) | 1 O (oxygen) | 4 Re (rhenium) | 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) H (hydrogen) | 1 | 1.008 O (oxygen) | 4 | 15.999 Re (rhenium) | 1 | 186.207 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) H (hydrogen) | 1 | 1.008 | 1 × 1.008 = 1.008 O (oxygen) | 4 | 15.999 | 4 × 15.999 = 63.996 Re (rhenium) | 1 | 186.207 | 1 × 186.207 = 186.207 M = 1.008 g/mol + 63.996 g/mol + 186.207 g/mol = 251.211 g/mol](../image_source/d01c5cc63f06fe4930d980a9a16940fa.png)
Find the molar mass, M, for perrhenic acid: 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: HReO_4 Use the chemical formula to count the number of atoms, N_i, for each element: | N_i H (hydrogen) | 1 O (oxygen) | 4 Re (rhenium) | 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) H (hydrogen) | 1 | 1.008 O (oxygen) | 4 | 15.999 Re (rhenium) | 1 | 186.207 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) H (hydrogen) | 1 | 1.008 | 1 × 1.008 = 1.008 O (oxygen) | 4 | 15.999 | 4 × 15.999 = 63.996 Re (rhenium) | 1 | 186.207 | 1 × 186.207 = 186.207 M = 1.008 g/mol + 63.996 g/mol + 186.207 g/mol = 251.211 g/mol
Unit conversion
![0.25121 kg/mol (kilograms per mole)](../image_source/757ab44a0fc443dd5521cf0ad15571f2.png)
0.25121 kg/mol (kilograms per mole)
Comparisons
![≈ 0.35 × molar mass of fullerene ( ≈ 721 g/mol )](../image_source/6ff2ad9f6816f543dce9c2f0101a3ed5.png)
≈ 0.35 × molar mass of fullerene ( ≈ 721 g/mol )
![≈ 1.3 × molar mass of caffeine ( ≈ 194 g/mol )](../image_source/bc1fe2a415a7ddea3d3bfd43f64de96d.png)
≈ 1.3 × molar mass of caffeine ( ≈ 194 g/mol )
![≈ 4.3 × molar mass of sodium chloride ( ≈ 58 g/mol )](../image_source/6060070efa4154d37416f92d242fc1ab.png)
≈ 4.3 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
![Mass of a molecule m from m = M/N_A: | 4.2×10^-22 grams | 4.2×10^-25 kg (kilograms) | 251 u (unified atomic mass units) | 251 Da (daltons)](../image_source/01e3f7dd5fb82b7b657932a9e6337b56.png)
Mass of a molecule m from m = M/N_A: | 4.2×10^-22 grams | 4.2×10^-25 kg (kilograms) | 251 u (unified atomic mass units) | 251 Da (daltons)
![Relative molecular mass M_r from M_r = M_u/M: | 251](../image_source/cb72441bca64ade49749c011b9621a6c.png)
Relative molecular mass M_r from M_r = M_u/M: | 251