F5 Chem molar volume of g

2011-04-23 2:10 am

100cm^3 of a mixture of gases (O2 and Ne) are sparked with 200cm^3 of hydrogen and the resulting gases have a volume of 210cm^3. All measurements are taken at room temperature and pressure. The volume of oxygen in the original mixture is
A. 30cm^3
B. 45cm^3
C. 80cm^3
D. 90cm^3

更新1:

Ans: A. Why??

回答 (1)

知識就是力量

2011-04-23 9:03 pm

✔ 最佳答案

Ne is a noble gas. It is unreactive and so it will not react with hydrogen.
Consider the equation: 2H2(g) + O2(g) --> 2H2O(l)
If 200cm^3 of hydrogen is reacted, 100cm^3 of oxygen is required.
So oxygen is limited (volume of oxygen < 100 cm^3)
Let x cm^3 be the volume of oxygen reacted
So volume of hydrogen reacted is 2x cm^3
=> hydrogen not being reacted = (200 - 2x)cm^3
and volume of neon = (100 - x)cm^3

(100 - x) + (200 - 2x) = 210
-3x = -90
x = 30
So the volume of oxygen in the original mixture is 30 cm^3.

2011-04-23 13:03:51 補充：
Ans: (A)

參考: Knowledge is power.

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