When sodium is heated in air, it catches fire and forms an oxide. If the sample is weighed before and after reaction, it is found to increase in mass by approximately 35%. On the other hand, when sodium is heated in pure oxygen, the reaction takes place more readily and the increase in mass is about 70%. Work out the simplest formulae of the two oxides of sodium.
Answer:
sodium oxide forms in air: Na2O
sodium oxide forms in pure oxygen: NaO
我想知step,, 同埋解釋埋比我聽.. thz
f.4 chem, about mole
2009-02-15 5:14 am
回答 (2)
2009-02-15 5:47 am
✔ 最佳答案
Molar mass of Na = 23 g/mol
Molar mass of O = 16 g/mol
When Na is heated in air:
Let the mass of Na in the oxide be y g.
Then, the mass of O in the oxide = 0.35y
Mole ratio Na : O
= (y/23) : (0.35y/16)
= 0.0435 : 0.0219
= 2 : 1
Hence, the simplest formula = Na2O
When Na is heated in pure oxygen:
Let the mass of Na in the oxide be x g.
Then, the mass of O in the oxide = 0.7x
Mole ratio Na : O
= (x/23) : (0.7x/16)
= 0.0435 : 0.0438
= 1 : 1
Hence, the simplest formula = NaO
=
2009-02-15 5:16 am
Please refer to the following link http://hk.knowledge.yahoo.com/question/question?qid=7008101902149
which is my previous answer.
which is my previous answer.
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