Kinetic Theory of Gases Questions and Answers

Vapour is injected at a uniform rate in a closed vessel Wi was initially evacuated The pressure in the vessel UPSEAT 2001 a Increases continuously b Decreases continuously c First increases and then decreases First increases and then becomes constant nts

d it The piston cylinder arrangement shown contains a diatomic gas at temperature 300 K The cross sectional area of the cylinder is1 m Initially the height of the piston above the base of the cylinder is 1 m The temperature is now raised to 400 K at constant pressure Find the new height of the piston above the base of the cylinder If the piston is now brought back to its original height without any heat loss find the new equilibrium temperature of the gas You can leave the answer in fraction DEF 20041 im

In a cubical box of volume V there are N molecules of a gas moving randomly If m is mass of each molecule and v2 is the mean square of x component of the velocity of molecules then the pressure of the gas is mNv SICS 1 P 3 V 3 P mNv 2 4 P mNv V P mNv

2 The atmospheric pressure on a hill is 68 cm of mercury What do you understand from the statement 3 How does atmospheric pressure change with the change in altitude 4 Briefly describe construction of a simple barometer

3 Which one of the following is not an assumption of kinetic theory of gases 1 The volume of a gas molecule is negligible 2 The gravitational attraction between the gas molecules is negligible 3 The density of gas is same at all points 4 The change in momentum of gas molecules is negligible

a 26 8 b 20 c 6 25 d 12 5 NEET 2018 At what temperature will the rms speed of oxygen molecules become just sufficient for escaping from the Earth s atmosphere Given Mass of oxygen molecule m 2 76 x 10 26 kg Boltzmann s constant kg 1 38 x 10 23 J K B a 2 508 x 104 K c 5 016 104 K b 8 360 x 10 K d 1 254 x 10 K NEET 2018 un eq of a 12 T t

1 A fix amount of nitrogen gas 1 mole is taken and is subjected to pressure and temperature variation The experiment is performed at high pressure as well as high temperatures The results obtained are shown in the figures The correct variation of PV RT with P will be exhibited by UPSEAT 2001 4 PV RT a 4 2 0 1 0 3 2 b 3 1 P 100 200 400 600

6 0 A vessel of volume 100 liter contains an ideal gas at pressure P and temperature T Gas is continuously pumped out of the vessel at a constant volume rate 5 lit sec kepping the temperature constant The pressure of a gas being taken out equals the pressure inside the vessel then find out time after which pressure Po of gas becomes 100 1 40 3 92 2 80

Gas phase sulfur S and gas phase oxygen O have the same molar mass At the same temperature they also have the same A C v B average KE per mole C average rotation KE per mole D average translational KE per mole

D 1 840 K 2 280 K 3 560 K 4 373 K Root mean square speed of ideal hydrogen gas in closed chamber at 0 C is 3180 m s Its pressure will be density of hydrogen gas is 8 99 10 kg m 1 atm 1 01 x 10 N m RPMT 2010 1 1 0 atm 2 1 5 atm 3 2 0 atm 4 3 0 atm upplied to raise the temperature of 50 gm of air from 20 C to 30 C without any change in its RPMT 2011

17 A solid body of constant heat capacity 1 J C is being heated by keeping it in contact with reservoirs in two ways 1 Sequentially keeping in contact with 2 reservoirs such that each reservoir supplies same amount of heat ii Sequentially keeping in contact with 8 reservoirs such that each reservoir supplies same amount of heat In both the cases body is brought from initial temperature 100 C to final temperature 200 C Entropy change of the body in the two cases respectively is a In2 2ln2 c In2 4ln2 b 21n2 8ln2 d In2 In2

The absolute temperature of a gas is increased to 16 times of origina temperature The root mean square speed of its molecule becomes Twice O Four times O One fourth O Halved

RMS speed of a monatomic gas is increased to two times of its initial value If the process is done adiabatically then the ratio of final volume to initial volume will be 1 1 4 2 1 8 3 1 23 2 12 3

68 An ideal gas follows a law according to that its pressure varies with volume as P 1 V B where a and are constants The temperature of the gas at volume V is equal to No of moles 1 1 3 a 2R a 2R 2 4 a 2R a R 74 75

A diatomic ideal gas initially at temperature T is enclosed in a cylinder fitted with a frictionless piston The gas is allowed to expand adiabatically to a temperature T If the lengths of gas column 2 in cylinder are L and L respectively then is T T 1 2 2 5 4 2 3 2 ong 4 5 2 3 2 4 12

9 A closed container having an ideal gas is heated gradually to increase the temperature by 20 The mean free path will become remain 2 Same 4 33 less 1 20 more 3 20 less

22 For the process A B of an ideal gas of fixed mass the density of gas P A B T 1 Increases 2 Decreases 3 Remains constant A First increases then decreases S 27

D Molar specific heat of oxygen at constant pressure Cp 7 2 cal mol C and R 8 3 J mol K At constant volume 5 mol of oxygen is heated from 10 C to 20 C the quantity of heat required is approximately 1 26 cal 2 360 cal 3 260 cal 4 500 cal

The ratio of specific heat at constant pressure to specific heat at constant volume Y for a gas is 1 where f is the number of degrees of freedom of a molecule of a gas The ratio of Ya for rigid diatomic to Ym for monoatomic is A B C D 14 23 25 21 21 25 23

The root mean square velocity of molecules of a gas is 200 m s What will be the root me square velocity of the molecules if the molecular weight is doubled and the absol Cemeprature is halved 100 m s A B 100 m s C 200 m s nce D 50 m s nce

of A is twice that of B Under such conditions the density of A is found to be 1 5 times th Two vessels separately contain two ideal gases A and B at the same temperature The pressur density of B The ratio of molecular weights of A and B is A 2 C 1 1 2 B 3 4 D CCR

This section contains 15 SINGLE CORRECT TYPE quest Read More A ideal gas taken through the cycle ABCA as shown in PV diagram The work done during the cycle is B 2P 2V A PV O PV O PV 2 O2PV C P 2V V

Two monoatomic ideal gases A and B of molecular masses m and respectively are enclosed in separate containers kept at the same temperature The ratio of the speed of sound in gas A to that in gas B is given by

At what temperature is the R M S Velocity of Hydrogen molecule equal to that of a molecule at 47 C Molecular weight of hydrogen A 20 K B 80 K Molecular weight of oxygen 3 C 60 K D 40 K

The average translational kinetic energy of one mole of 02 molecules molar mass 32 at a particular temperature is 0 048 eV The internal energy of one mole of N2 molecules molar mass 28 in eV at same temperature is Answer A Your Attempt 0 048 Rate this question Correct answer J

For an ideal gas if the ratio of Molar specific heats y 1 4 then the specific heat at con pressure Cp specific tat constant volume C and corresponding molecule are respective 7 diatomic 9 27 2 A R R polyatomi CRR rigid R rigid diatomic 7 B R R non RR D R R monoatomic

Internal energy of n moles of hydrogen at temperature T is equal to the internal energy of n2 moles of helium at temperature 2T The value of ratio is neglect vibrational modes in hydrogen n 613

Which of the following is not an assumption of kinetic theory of gases The volume occupied by the molecules of the gas is negligible in comparison to the volume of the container O Intermolecular force of attraction repulsion between the molecules is negligible O All molecules of a gas move with equal speed O The collision between the molecules with the wall of container are elastic

A vessel has 10 g of hydrogen gas at pressure P and temperature 400 K A small hole is made in it so that hydrogen leaks out How much hydrogen leaks out if the final pressure becomes half and temperature becomes th of its previous value 01g 23

If Cp and Cydenoted the specific heat of unit gram mass of nitrogen at constant pressure and volume respectively then R is universal gas constant O Cp Cv R O Cp Cv 7R O 28 Cp Cv R O Cp Cy 28R

Internal energy of n moles of hydrogen at temperature is equal to the internal energy of n moles of helium at temperature 27 The value of ratio is neglect n n vibrational modes in hydrogen wo ch 314 6 8

010 Ideal gas in a closed container initially having volume V and pressure P If the final pressure is 4P and volume is kept constant what is the ratio of the initial kinetic energy with final kinetic energy O A 12 O 8 4 1 0 0 21 O D 14

Cooking gas containers are kept in a lorry moving with uniform speed The temperature of the gas molecules inside will 47 2 decrease 273 remain same 4 decrease for some while increase for others 320 At what temperature is the rms velocity of a hydrogen molecule equal to that of an oxygen molecule at 47 C 1 increase

1 m of a gas is compressed suddenly at atmospheric pressure and temperature 27 C such that its temperatu becomes 627 C The final pressure of gas will be y 1 5 1 27 x 105 N m 2 7 2 x 105 N m 3 2 7 x 105 N m 4 27 x 105 N m in the whole cycle

MT 2 2 MLT 3 MLT 4 LT Some students find values of C and C for a gas in calorie gm mol K Which pair is most correct RPMT 2010 P 1 C 3 C 5 4 C 3 C 42 Hydrogen gas is filled in a container of volume 20 litre Average translational kinetic energy of all its molecules is 1 5 2 C 4 C 6 3 C 3 C 2 IRPMT 2010

Three closed vessels A B and C are at the same temperature T and contain gases which obey the Maxwellian distribution of velocities Vessel A contains only O B only N and C a mixture of equal quantities of O and N If the average speed of O molecules in vessel A is V that of the N molecules in vessel B is V the average speed of the O molecules in vessel C will be 1 V V 2 2 V 3 V V 2 4 3KT M EV N 8

1 kinetic energy The average momentum 1 temperature 2 momentum 3 density of a molecule in a sample of an ideal gas depends on 2 number of moles 3 volume 4 speed 4 none of thes

When an ideal gas is compressed isothermally then its pressure increases because 1 its potential energy decreases 2 Its kinetic energy increases and molecules move apart 3 its number of collisions per unit area with walls of container increases 4 molecular energy increases

An HCl molecule has rotational vibrational motions If the rms velocity of HCI molecules in its gaseous phase is v m is its mass kg is Boltzmann constant then its temperature will be mv b 3kB a mv 7KB c mv 5kB d mv 6kB April 201

A cylinder contains SO2 gas at a pressure of 4 1 atmosphere and at 47 C temperature The density of the gas in the cylinder is 0 2 g ml 0 4 g ml 0 01 g ml 10 g ml

In an isobaric process of a monoatomic gas of heat is added to n moles of the gas to increase temperature from T to T The amount of work done by the gas in the process is 1 20 J 3 60 J 2 30 J 4 40 J 00 for an ideal

An ideal gas heat engine operates in a Carnot cycle between 227 C and 327 C It absorbs 6 kcal at the higher temperature The amount of heat in kcal converted into work is equal to Question Type Single Correct Type 1 5 2 3 5 3 2 8

27 During an adiabatic process the pressure of a gas is found to be proportional to the cube of its Gp for the gas is Gy PQ T v cont VY V temperature The ratio of 1 Y a 4I3 In the mi 3 arring on b 2 92 191 P2 c 5o 3 P1 1067 T 1024 NEET 2013 d 312

D 1 2 2 1 2 An ideal gas is compressed to half its initial volume by means of several processes Which of the process results in the maximum work done on the gas NEET 205 1 isochoric 2 isothermal 3 adiabatic isobaric works between 4 C and 30 C It is required to remove 600 calories of heat every second in order to 120

01 Section B Graph of specific heat at constant volume for a monoatomic gas is C 1 2 Cy Previous Year 3 R 3R 2 4 Cy T AHMS 2013 TI TI T 1 mola of hydrogen is mixed with I mole of neon The molar specific heat at constant pressure is AIIMS 2014

02 mp T TI 3 mole of hydrogen is mixed with 1 mole of neon The molar specific heat at constant pressure is AIIMS 2014 1 9R 4 13R 2 13R 9R 4 2 73 2 4 ntained in a box of volume V 1 00 m at T 300 K The gas is heated to a temperature of T

Answer to each question will be evaluated according to the following marking scheme Full Marks 4 If only all the correct option s is are chosen Partial Marks 3If all the four options are correct but ONLY three options are chosen Partial Marks 2 If three or more options are correct but ONLY two options are chosen both of which are correct options Partial Marks 1 If two or more options are correct but ONLY one option is chosen and it is a correct option Zero Marks 0 If none of the options is chosen i e the question is unanswered Negative Marks 2 In all other cases For Example If first third and fourth are the ONLY three correct options for a question with second option being an incorrect option selecting only all the three correct options will result in 4 marks Selecting on second option in this case will result in 2 marks Selecting only one of the three correct options either first or third fourth option without selecting any incorrect option second option in this case will result in correct option s will result in 2 marks Q A polytropic process for an ideal gas is represent by PV constant X 1 An amount of heat is added to a monatomic ideal gas in a process in which the gas preforms a work 2 on its surroundings ther The process i isobaric The value of x 1 3 The molar specific heat capacity of the gas in this process is 4R

4 The work done in an adiabatic process is always zero Two thermally insulated vessels 1 and 2 are filled with air at temperature T T volume V V and pressure P P respectively If the valve joining the two vessels is opened the temperature inside the vessel at equilibrium will be AIEEE 2004 1 T T 2 T T 2 T T PV P V 4 PVT P V T T T PV P V 3 PV T P V T Which of the following is incorrect regarding the first law of thermodynamics AIEEE 2005

P m P m P m P m P m P m When an ideal monoatomic gas is heated at constant pressure the fraction of the heat energy supplied which increases the internal energy of the gas is AIIMS 2017 1 2 5 12 3 5 3 3 7 4 5 7 carnot engine operates with source at 127 C If the source supplies 40 kJ of heat energy the work done by the JAIIMS 2017

Select the incorrect relation Where symbols haw their usual meanings 1 Cp YR Y 1 3 AU PV PV 1 Y www a non 2 Cp Cv R R Y 1 depend