Input interpretation
![arsenic acid, solid | molar mass](../image_source/271cc018e4dfc18b12a52f10bdb5d327.png)
arsenic acid, solid | molar mass
Result
![Find the molar mass, M, for arsenic acid, solid: 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: H_3AsO_4 Use the chemical formula to count the number of atoms, N_i, for each element: | N_i As (arsenic) | 1 H (hydrogen) | 3 O (oxygen) | 4 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) As (arsenic) | 1 | 74.921595 H (hydrogen) | 3 | 1.008 O (oxygen) | 4 | 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) As (arsenic) | 1 | 74.921595 | 1 × 74.921595 = 74.921595 H (hydrogen) | 3 | 1.008 | 3 × 1.008 = 3.024 O (oxygen) | 4 | 15.999 | 4 × 15.999 = 63.996 M = 74.921595 g/mol + 3.024 g/mol + 63.996 g/mol = 141.942 g/mol](../image_source/9e3824a692083fc4464370dc72754e40.png)
Find the molar mass, M, for arsenic acid, solid: 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: H_3AsO_4 Use the chemical formula to count the number of atoms, N_i, for each element: | N_i As (arsenic) | 1 H (hydrogen) | 3 O (oxygen) | 4 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) As (arsenic) | 1 | 74.921595 H (hydrogen) | 3 | 1.008 O (oxygen) | 4 | 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) As (arsenic) | 1 | 74.921595 | 1 × 74.921595 = 74.921595 H (hydrogen) | 3 | 1.008 | 3 × 1.008 = 3.024 O (oxygen) | 4 | 15.999 | 4 × 15.999 = 63.996 M = 74.921595 g/mol + 3.024 g/mol + 63.996 g/mol = 141.942 g/mol
Unit conversion
![0.14194 kg/mol (kilograms per mole)](../image_source/87806d114416e73cd43df153b3b71a8e.png)
0.14194 kg/mol (kilograms per mole)
Comparisons
![≈ ( 0.2 ≈ 1/5 ) × molar mass of fullerene ( ≈ 721 g/mol )](../image_source/40b6c9fb6adabd99a8bfbba0cd4e293d.png)
≈ ( 0.2 ≈ 1/5 ) × molar mass of fullerene ( ≈ 721 g/mol )
![≈ 0.73 × molar mass of caffeine ( ≈ 194 g/mol )](../image_source/a5727bc7da18e694276cbf45a0589510.png)
≈ 0.73 × molar mass of caffeine ( ≈ 194 g/mol )
![≈ 2.4 × molar mass of sodium chloride ( ≈ 58 g/mol )](../image_source/3049b7510ff016736e61154da3f6dc01.png)
≈ 2.4 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
![Mass of a molecule m from m = M/N_A: | 2.4×10^-22 grams | 2.4×10^-25 kg (kilograms) | 142 u (unified atomic mass units) | 142 Da (daltons)](../image_source/cec25595762acbc4d93a51589f95e0a3.png)
Mass of a molecule m from m = M/N_A: | 2.4×10^-22 grams | 2.4×10^-25 kg (kilograms) | 142 u (unified atomic mass units) | 142 Da (daltons)
![Relative molecular mass M_r from M_r = M_u/M: | 142](../image_source/3f29c1b0795ab3c91bd0255e29ea9bbb.png)
Relative molecular mass M_r from M_r = M_u/M: | 142