# At 0°C, the Density of a Certain Oxide of a Gas at 2 Bar is Same as that of Dinitrogen at 5 Bar. What is the Molecular Mass of the Oxide? - Chemistry

Numerical

At 0°C, the density of a certain oxide of a gas at 2 bar is same as that of dinitrogen at 5 bar. What is the molecular mass of the oxide?

#### Solution

Density (d) of the substance at temperature (T) can be given by the expression,

d = "Mp"/"RT"

Now, density of oxide (d1) is given by,

"d"_1 = ("M"_1"p"_1)/"RT"

Where, M1 and p1 are the mass and pressure of the oxide respectively.

Density of dinitrogen gas (d2) is given by,

"d"_2 = ("M"_2"p"_2)/"RT"

Where, M2 and p2 are the mass and pressure of the oxide respectively.

According to the given question,

"d"_1 = "d"_2

therefore "M"_1"p"_1 = "M"_2"p"_2

Given

"p"_1 =  "2 bar"

"p"_2 = "5 bar"

Molecular mass of nitrogen, M2 = 28 g/mol

Now "M"_1 = ("M"_2"p"_2)/"p"_1

= (28xx5)/2`

= 70 g/mol

Hence, the molecular mass of the oxide is 70 g/mol.

Is there an error in this question or solution?
Chapter 5: States of Matter - EXERCISES [Page 158]

#### APPEARS IN

NCERT Chemistry Part 1 and 2 Class 11
Chapter 5 States of Matter
EXERCISES | Q 5.4 | Page 158

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