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question_answer1)
Two closed vessels of equal volume containing air at pressure \[{{P}_{1}}\] and temperature \[{{T}_{1}}\] are connected to each other through a narrow tube. If the temperature in one of the vessels is now maintained at \[{{T}_{1}}\] and that in the other at \[{{T}_{2}}\], what will be the pressure in the vessels?
A)
\[\frac{2{{P}_{1}}{{T}_{1}}}{{{T}_{1}}+{{T}_{2}}}\] done
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B)
\[\frac{{{T}_{1}}}{2{{P}_{1}}{{T}_{1}}}\] done
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C)
\[\frac{2{{P}_{1}}{{T}_{2}}}{{{T}_{1}}+{{T}_{2}}}\] done
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D)
\[\frac{2{{P}_{1}}}{{{T}_{1}}+{{T}_{2}}}\] done
clear
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question_answer2)
The volume of a gas increases by a factor of 2 while the pressure decreases by a factor of 3. Given that the number of moles is unaffected, the factor by which the temperature changes is:
A)
\[\frac{3}{2}\] done
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B)
\[3\times 2\] done
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C)
\[\frac{2}{3}\] done
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D)
\[\frac{1}{2}\times 3\] done
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question_answer3)
The ratio among most probable velocity, mean velocity and root mean square velocity is given by
A)
\[1:2:3\] done
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B)
\[1:\sqrt{2}:\sqrt{3}\] done
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C)
\[\sqrt{2}:\sqrt{3}:\sqrt{8/\pi }\] done
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D)
\[\sqrt{2}:\sqrt{8/\pi }:\sqrt{3}\] done
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question_answer4)
The rms speed of \[{{N}_{2}}\] molecules in a gas is \[u\]. If the temperature is doubled and the nitrogen molecules dissociate into nitrogen atoms, the rms speed becomes
A)
\[u/2\] done
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B)
\[2u\] done
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C)
\[4u\] done
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D)
\[14u\] done
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question_answer5)
The correct order of normal boiling points of \[{{O}_{2}}\], \[{{N}_{2}}\], \[N{{H}_{3}}\] and \[C{{H}_{4}}\] for whom the values of van der Waals constant \['a'\] are 1.360, 1.390, 4.170 and 2.253 \[{{L}^{2}}\] atm \[mo{{l}^{-2}}\] respectively, is:
A)
\[{{O}_{2}}<{{N}_{2}}<N{{H}_{3}}<C{{H}_{4}}\] done
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B)
\[{{O}_{2}}<{{N}_{2}}<C{{H}_{4}}<NH\] done
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C)
\[N{{H}_{3}}\]\[<C{{H}_{4}}\]\[<{{N}_{2}}\]\[<\]\[{{O}_{2}}\] done
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D)
\[N{{H}_{3}}\]\[<C{{H}_{4}}\]\[<\]\[{{O}_{2}}\]\[<{{N}_{2}}\] done
clear
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question_answer6)
Two gases A and B present separately in two vessels X and Y at the same temperature with molecular weights M and 2M respectively are effused out. The orifice in vessel X is circular while that in Vis a square. If the radius of the circular orifice is equal to that of the length of the square orifice, the ratio of rates of effusion of gas A to that of gas B is
A)
\[\sqrt{2}\pi \] done
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B)
\[\sqrt{\frac{\pi }{2}}\] done
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C)
\[2\pi \] done
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D)
\[\sqrt{\frac{2}{\pi }}\] done
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question_answer7)
Dipole-dipole interaction energy between stationary polar molecules is proportional to x and that between rotating molecules is proportional to y. Assume distance between polar molecules as r, then x and y are
A)
\[\frac{1}{{{r}^{6}}},\frac{1}{{{r}^{3}}}\] done
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B)
\[\frac{1}{{{r}^{6}}},\frac{1}{{{r}^{6}}}\] done
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C)
\[\frac{1}{{{r}^{3}}},\frac{1}{{{r}^{3}}}\] done
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D)
\[\frac{1}{{{r}^{3}}},\frac{1}{{{r}^{6}}}\] done
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question_answer8)
A vessel of volume 5 litres contains 1.4 g of nitrogen at a temperature 1800 K. The pressure of the gas if 30% of its molecules are dissociated into atoms at this temperature is
A)
4.05 atm done
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B)
2.025 atm done
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C)
3.84 atm done
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D)
1.92 atm done
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question_answer9)
A balloon containing 1 mole air at 1 atm initially is filled further with air till pressure increases to 4 atm. The initial diameter of the balloon is 1 m and the pressure at each stage is proportion to diameter of the balloon. How many no. of moles of air added to change the pressure from 1 atm to 4 atm:
A)
80 done
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B)
257 done
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C)
255 done
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D)
256 done
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question_answer10)
Total pressure of a mixture of \[{{H}_{2}}\] and \[{{O}_{2}}\] is 1.00 bar. The mixture is allowed to react to form water, which is completely removed to leave only pure \[{{H}_{2}}\] at a pressure of 0.35 bar. Assuming ideal gas behaviour and that all pressure measurements were made under the same temperature and volume conditions, the composition of the original mixture is
A)
B)
C)
D)
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question_answer11)
At what temperature will the total KE of 0.3 mol of He be the same as the total KE of 0.40 mol of Ar at 400 K?
A)
533 K done
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B)
400 K done
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C)
346 done
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D)
300 K done
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question_answer12)
Select the correct statement
A)
When attractive forces are dominant in a real gas U internal energy increases by increasing the average molecular separation done
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B)
Isothermal contraction decreases the internal energy when repulsive forces between molecules exist done
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C)
For an ideal gas at constant T internal energy is function of volume only. done
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D)
In case of attractive forces between particle, if the volume of the sample expands isothemlally its dU< 0 done
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question_answer13)
A gas obeys P(V - b) = RT. Which of the following is correct about this gas?
I. Isochoric curves have slope =\[\frac{V-b}{R}\] |
II. sobaric curves have slope \[\frac{R}{P}\] and intercept b. |
III. For the gas, compressibility factor = \[1+\frac{Pb}{RT}\] |
IV. The attraction forces are overcome by repulsive forces. |
A)
I done
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B)
II, III, IV done
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C)
III done
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D)
I, II, III, IV done
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question_answer14)
The compressibility factor for definite amount of van der Waals' gas at \[0{}^\circ C\]and 100 atm is found to be 0.5. Assuming the volume of gas molecules negligible, the van der Waals' constant a for a gas is
A)
1.256 \[{{L}^{2}}mo{{l}^{-2}}atm\] done
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B)
0.256 \[{{L}^{2}}mo{{l}^{-2}}atm\] done
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C)
2.256 \[{{L}^{2}}mo{{l}^{-2}}atm\] done
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D)
0.0256 \[{{L}^{2}}mo{{l}^{-2}}atm\] done
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question_answer15)
Relative humidity of air is \[60{}^\circ \] and the saturation vapour pressure of water vapour in air is 3.6 k Pa. The amount of water vapours present in 2 L air at 300 K is
A)
52 g done
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B)
31.2 g done
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C)
26 g done
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D)
5.2 g done
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question_answer16)
In the van der Waals equation
A)
b is the volume occupied by the gas molecules done
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B)
b is four times the volume occupied by the gas molecules done
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C)
b is the correction factor for intermolecular attraction done
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D)
None of these done
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question_answer17)
The root mean square velocity of an ideal gas to constant Pressure varies with density as
A)
\[{{d}^{2}}\] done
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B)
\[d\] done
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C)
\[\sqrt{d}\] done
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D)
\[1/\sqrt{d}\] done
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question_answer18)
When the temperature increases, the surface tension of water
A)
Increases done
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B)
Decreases done
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C)
Remains constant done
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D)
Shows irregular behaviour done
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question_answer19)
Positive deviation from ideal behaviour takes place because of
A)
The molecular interaction between atom and \[PV/nRT>1\] done
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B)
The molecular interaction between atom and \[PV/nRT<1\] done
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C)
The-finite size of atoms and \[PV/nRT>1\] done
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D)
The finite size of atoms and \[PV/nRT<1\] done
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question_answer20)
If Z is a compressibility factor, van der Waals equation at low pressure can be written as
A)
\[Z=1-\frac{Pb}{RT}\] done
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B)
\[Z=1+\frac{Pb}{RT}\] done
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C)
\[Z=1+\frac{RT}{Pb}\] done
clear
D)
\[Z=1-\frac{a}{VRT}\] done
clear
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question_answer21)
Calculate the molecular weight of a gas whose density at \[40{}^\circ C\]and 785 mm of Hg pressure is 1.3 g \[{{L}^{-1}}\].
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question_answer22)
A vessel contains 0.1 mole of He, 0.1 mole of \[{{O}_{2}}\] and0.3 moles of\[{{N}_{2}}\]. The total pressure is 1 atmosphere. The pressure exerted by \[{{O}_{2}}\] is
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question_answer23)
An effusion experiment requires 40 s for a certain number of moles of a gas of unknown molar mass to pass through a small orifice into a vacuum. Under the same conditions, 16s was required for the same number of moles of \[{{O}_{2}}\] to effuse. The molar mass of the unknown gas is
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question_answer24)
A gas cylinder containing cooking gas can withstand a pressure of 14.9 atm. The pressure gauge of cylinder indicates 12 atm at \[27{}^\circ C\]. Due to sudden fire in building the temperature starts rising. The temperature at which the cylinder will explode is
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question_answer25)
A 8.3 L cylinder contains 128.0 g \[{{O}_{2}}\] gas at \[27{}^\circ C\]. The mass of \[{{O}_{2}}\] gas must be released to reduce the pressure to 6.0 bar is
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