Input interpretation
![zinc dichromate | molar mass](../image_source/e8bd0068a2a237081cd5e7d2007da3a0.png)
zinc dichromate | molar mass
Result
![Find the molar mass, M, for zinc dichromate: 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: ZnCr_2O_7 Use the chemical formula to count the number of atoms, N_i, for each element: | N_i Cr (chromium) | 2 O (oxygen) | 7 Zn (zinc) | 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) Cr (chromium) | 2 | 51.9961 O (oxygen) | 7 | 15.999 Zn (zinc) | 1 | 65.38 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) Cr (chromium) | 2 | 51.9961 | 2 × 51.9961 = 103.9922 O (oxygen) | 7 | 15.999 | 7 × 15.999 = 111.993 Zn (zinc) | 1 | 65.38 | 1 × 65.38 = 65.38 M = 103.9922 g/mol + 111.993 g/mol + 65.38 g/mol = 281.37 g/mol](../image_source/0d8166ac263af9d856deefaf240d4524.png)
Find the molar mass, M, for zinc dichromate: 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: ZnCr_2O_7 Use the chemical formula to count the number of atoms, N_i, for each element: | N_i Cr (chromium) | 2 O (oxygen) | 7 Zn (zinc) | 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) Cr (chromium) | 2 | 51.9961 O (oxygen) | 7 | 15.999 Zn (zinc) | 1 | 65.38 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) Cr (chromium) | 2 | 51.9961 | 2 × 51.9961 = 103.9922 O (oxygen) | 7 | 15.999 | 7 × 15.999 = 111.993 Zn (zinc) | 1 | 65.38 | 1 × 65.38 = 65.38 M = 103.9922 g/mol + 111.993 g/mol + 65.38 g/mol = 281.37 g/mol
Unit conversion
![0.28137 kg/mol (kilograms per mole)](../image_source/dbbbef7424e5d56050ca58e52c3045a6.png)
0.28137 kg/mol (kilograms per mole)
Comparisons
![≈ 0.39 × molar mass of fullerene ( ≈ 721 g/mol )](../image_source/bad5114121062f1e3feaaee51978ab1b.png)
≈ 0.39 × molar mass of fullerene ( ≈ 721 g/mol )
![≈ 1.4 × molar mass of caffeine ( ≈ 194 g/mol )](../image_source/3a5941b42e2a0d4f508b3465a828ace3.png)
≈ 1.4 × molar mass of caffeine ( ≈ 194 g/mol )
![≈ 4.8 × molar mass of sodium chloride ( ≈ 58 g/mol )](../image_source/f16a032b34413f824488b5844d11c33b.png)
≈ 4.8 × molar mass of sodium chloride ( ≈ 58 g/mol )
Corresponding quantities
![Mass of a molecule m from m = M/N_A: | 4.7×10^-22 grams | 4.7×10^-25 kg (kilograms) | 281 u (unified atomic mass units) | 281 Da (daltons)](../image_source/a21c1db25d1bbecaaaeb0aaeaa36948e.png)
Mass of a molecule m from m = M/N_A: | 4.7×10^-22 grams | 4.7×10^-25 kg (kilograms) | 281 u (unified atomic mass units) | 281 Da (daltons)
![Relative molecular mass M_r from M_r = M_u/M: | 281](../image_source/e1a3030cb74baa8b6ab6c0a566a11628.png)
Relative molecular mass M_r from M_r = M_u/M: | 281