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Calculate the molar mass of i) Sodium oxide ii) Ammonia. (Given, the atomic mass of Sodium = 23u, Oxygen=16u, Nitrogen=14u and Hydrogen=1u) |
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Answer» Explanation:i)The molecular mass of sodium oxide is the sum of 2 Sodium atoms and one Oxygen atom or 62 amu Sodium has a mass of 23 amu. Since there two Sodium the mass of Sodium in the molecules is 2×23=46 amu. Oxygen Atomic number 8 has 8 protons and 8 neutrons, for a mass of 16 amu for the mass of oxygen in the molecule is 16 amu since there is only one Oxygen atom in the molecule Add the mass of the sodium ( 46 amu ) with the mass of Oxygen ( 16 amu) to find the mass of the molecule 46 amu+16 amu=62 amu II)The atomic masses of N and H are 14 g/mol and 1 g/mol respectively. The molecular weight of AMMONIA is 14+3(1)=17 g/mol. Convert unit from g to kg 17 g/mol× 1000 g 1 kg =0.017 kg/mol 1 MOLE of ammonia weighs 0.017 kg and contains AVOGADRO's number ( 6.023×10 23 ) of molecules. Molecular mass of an ammonia molecule = 6.023 ×10 23 molecules/mol 0.017 kg/mol =2.82×10 −26 kg |
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