Input interpretation
![molybdenum(IV) selenide | molar mass](../image_source/ff5260ec3201618ec6cd62ce7f41fa9b.png)
molybdenum(IV) selenide | molar mass
Result
![Find the molar mass, M, for molybdenum(IV) selenide: 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: MoSe_2 Use the chemical formula to count the number of atoms, N_i, for each element: | N_i Mo (molybdenum) | 1 Se (selenium) | 2 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) Mo (molybdenum) | 1 | 95.95 Se (selenium) | 2 | 78.971 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) Mo (molybdenum) | 1 | 95.95 | 1 × 95.95 = 95.95 Se (selenium) | 2 | 78.971 | 2 × 78.971 = 157.942 M = 95.95 g/mol + 157.942 g/mol = 253.89 g/mol](../image_source/cab55515279eaeeee8c7660b8e02bb43.png)
Find the molar mass, M, for molybdenum(IV) selenide: 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: MoSe_2 Use the chemical formula to count the number of atoms, N_i, for each element: | N_i Mo (molybdenum) | 1 Se (selenium) | 2 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) Mo (molybdenum) | 1 | 95.95 Se (selenium) | 2 | 78.971 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) Mo (molybdenum) | 1 | 95.95 | 1 × 95.95 = 95.95 Se (selenium) | 2 | 78.971 | 2 × 78.971 = 157.942 M = 95.95 g/mol + 157.942 g/mol = 253.89 g/mol
Unit conversion
![0.2539 kg/mol (kilograms per mole)](../image_source/0c9cca77926ca1cb495b02f3763f62f9.png)
0.2539 kg/mol (kilograms per mole)
Comparisons
![≈ 0.35 × molar mass of fullerene ( ≈ 721 g/mol )](../image_source/7308a1ae28e2aae240726a4f0030f0f1.png)
≈ 0.35 × molar mass of fullerene ( ≈ 721 g/mol )
![≈ 1.3 × molar mass of caffeine ( ≈ 194 g/mol )](../image_source/88280adcb61ccbdab526f52a6989fab4.png)
≈ 1.3 × molar mass of caffeine ( ≈ 194 g/mol )
![≈ 4.3 × molar mass of sodium chloride ( ≈ 58 g/mol )](../image_source/15c33bd434615756ab853d9309f4a78b.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) | 254 u (unified atomic mass units) | 254 Da (daltons)](../image_source/3865cd602898323bf1ba79a95016af06.png)
Mass of a molecule m from m = M/N_A: | 4.2×10^-22 grams | 4.2×10^-25 kg (kilograms) | 254 u (unified atomic mass units) | 254 Da (daltons)
![Relative molecular mass M_r from M_r = M_u/M: | 254](../image_source/17d3a1387f27d845e68e9b0106bc3b0e.png)
Relative molecular mass M_r from M_r = M_u/M: | 254