Calculate the molar mass of i) Sodium oxide ii) Ammonia.
(Given, the atomic mass of Sodium = 23u, Oxygen=16u, Nitrogen=14u
and Hydrogen=1u)
Answers
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
Answer:
. In a reaction 5.3 g of sodium carbonate reacted with 6 g of ethanoic acid. The products were 2.2 g of carbon dioxide, 0.9 g water and 8.2 g of sodium ethanoate. Show that these observations are in agreement with the law of conservation of mass carbonate.
Ans.
Sodium carbonate + Ethanoic acid → Sodium ethanoate + Carbon dioxide + Water
5.3 g + 6 g → 8.2 g + 2.2 g + 0.9 g
LHS RHS
11.3 g = 11.3 g
(Mass of reactant) (Mass of product)
This shows, that during a chemical reaction mass of reactact = mass of product.