Gaseous and liquid states Questions and Answers

28 The enthalpy of combustion of H cyclohexene C H and cyclohexane C H are 241 3800 and 3920 kJ per mol respectively Heat of hydrogenation of cyclohexene is AIPMT Prelims 2006 1 121 kJ per mol 2 121 kJ per mol 3 242 kJ per mol Sol Answer 1 4 242 kJ per mol

In the following question a statement of assertion is followed by a statement of reason Choose the correct answer out of the following choices Assertion The electrons in different subshells have different energies in a multielectron atom Reason The energy of an orbital depends on n value A B Both assertion and reason are correct and the reason is the correct explanation of the assertion Both assertion and the reason are correct but the reason is not the correct explanation of the assertion C Assertion is true but the reason is false D Both assertion and reason are false statements

100 ml of a solution containing NaHCO3 Na CO3 required 50 ml of 0 1 M HCI to reach the phenolphthalein end point But the same volume of this solution required 125 ml of 0 2 M HCI to reach the methyl orange end point The molarities with respect to HCO3 and CO ions in the solution would be respectively A 0 05 0 05 C 0 025 0 025 B 0 025 0 05 D 0 15 0 05

Which of the following is correct for critical temperature AY It is the temperature at which liquid and vapour can coexist BY Beyond the critical temperature there is single phases and a gas cannot be liquified by compres C Below critical temperature Tc the gas can be liquified at all pressure D At critical point the gas and the liquid phases have different critical densities

35 P 10 atm V 800 ml 3 Fig I Fig II In the above figures a doll is entrapped within a piston and cylinder containing gas Initial and final conditions are shown Figure I and Figure II respectively Th volume of doll is 1 1000 ml 1000 3 ml P 7 atm V 1000 ml 2 4 15000 17 1000 15 ml ml

Separate samples of two gases each containing a pure substance are found to have the same density under the same conditions of temperature and pressure Which statement about these two samples must be correct A They have the same volume B They have the same relative molecular mass C There are equal numbers of moles of gas in the two samples

t moderate pressure the compressibility factor for a particular gas is given by 2000P Z 1 0 2P T dentify the correct statements A B C D Below 50K at all temperatures gas can be liquefied by applying high pressure Gas shows ideal behavior at 100 K When gas is subjected to Joule Thomson effect above 200K temperature of cylinder increases Gas is easily liquefied between 50K to 100K and above 100K it is not possible to liquify gas by applying high pressure YOU MARK YOU MARK YOU MARK

1 a what is the mass of NaNO3 required to make 50 00 mL of a 0 1500 M solution b find absolute uncertainty in the molar mass of NaNO3 c Calculate the absolute uncertainty in the concentration assuming that the balance is precise to 0 1 mg and that the volumetric flask is calibrated and precise to 0 05 mL Please provide all the steps as well as the correct number of significant figures

Avogadros Law given Starting Volume width in nm 5 0 nm effect on Volume constant Starting Temp K 300K effect on temp 300k Starting Pressure atm 23 3 atm Effect on pressure atm constant 23 3 Number of Gas Particles 100 heavy 100 H 200H This is Gas Laws PhET simulation

7 A liquid mixture of 50 mole n butane and 50 mole n pentane at 60 C and total pressure of 2600 mm Hg At equilibrium find the composition of both the liquid and vapor phases What fraction of the original liquid was vaporized If the mixture is heated further to 80 C what is the resulting pressure

la A real gas is placed in a container if intermolec attraction are supposed to disappear suddenly ther 1 The pressure decreases 2 The pressure increases 3 The pressure remain unchanged 4 The gas collapsest H

A gaseous mixture of H and He in the mass ratio 1 4 is successively effused through a series of containers connected through narrow tubes of negligible volume and fitted wit valves The valves are successively opened for a very small time interval Find the minimum number of effusion steps required to obtain a molar ratio 8 1 for H and He after the effusion process

A gas mixture of volumetric composition 45 CO 50 CO2 and 5 N was passed over ZnO at 1380 K so that Zn vapours was produced according to the reaction ZnO s CO g Zn g CO2 g Under steady condition the rate of input gas flow at STP is 0 224 dm min The rate of loss of mass of ZnO is 5 x 10 4 mol min P 770 torr Find Kp at gas behaviour 1380 K assuming ideal a 0 507 atm c 0 664 atm b 0 0664 atm d 0 325 atm

The liquefaction behaviour of temporary gases like CO approaches that of N O permanent gases as we go 1 Below absolute zero 2 Above absolute zero 3 Above critical temperature 4 Below critical temperature ar Y Y 7 and c respectively where

4 The pressure exerted by 6 0 g of methane gas in a 0 03 m vessel at 129 C is Atomic masses C 12 01 H 1 01 and R 8 314 JK mol AIPMT Mains 2010 1 215216 Pa 2 13409 Pa 3 41648 Pa 01 02

of 1 atm 0 1 mol of He and 1 0 To an evacuated vessel with movable piston under extern reduced Considering the ideal gas be an unknown compound vapour pressure 0 68 atm at 0 C are the total volume in litre of the gases at 0 C is close to ash

gases Column I A Hydrogen gas P 200 atm T 273 K B Hydrogen gas P 0 T 273 K C CO P 1 atm T 273 K n ONL Column II p Compressibility factor 1 q Attractive forces are r PV nRT 6 D06 IIT JEE hinant

A gas is filled in the glass bulb of capacity 10 litre as shown in figure at 300 K Density of glycerine 2 72 g ml Density of mercury 13 6 g ml Now select the correct statement s among the following A pressure of the gas is 3 28 atm B pressure of the gas is 0 342 atm C moles of the gas in the bulb are 0 34 D moles of the gas in the bulb are 1 33 10 t Glicerine 2 5m Air 1 atm

Example 7 42 Following two equilibria are establ mixing two gases A and C i 3A g A g ii A g C g A C g 23 c K 1 6 atm P 020 If A and C are mixed in 2 1 molar ratio calculate the equilibrium partial pressures of A C A C and K for the reaction ii Given that the total pressure to be 1 4 atm and to ho 02 atm at equilibrium

31 From the following pairs select the one in which both samples contain same number of atoms 1 2 4 g of O and 4 2 g of N 2 4 4 g of CO2 and 4 6 g of Na 3 1 4 g of H SO4 and 560 mL of SO g at STP 4 6 023 10 molecules of H3PO4 and 7 3 g of HC

Using van dar Waals equation of state calculate pressure in atm developed by 132 g of CO2 contained in a volume of 6 0 litre at 27 C a 3 6 atm L mol 2 b 400 cm mol R 0 08 L atm k mol

3 1 mol of monoatomic ideal gas at 300 K expands from 1 L to 8 L in two different process Process I Reversible adiabatic expansion Process II Irreversible adiabatic expansion against the constant external pressure of 1 atm given 1 atm L 101 J Select the correct statement 1 W Process WProcess I 2 Tflprocess T Process 11 f 11 f final 3 TflProcess 1 IT fl Process II f final I 4 Change in internal energy in process II is less than change in internal energy of process

49 ub N O4 9 2NO g Kp2 2 The degree of dissociations are equal for both the above reactions If their equilibrium pressures are also in the ratio of 4 1 then ratio of Kp to Kp2 is 1 1 2 estel Two equilibrium reactions are taken in different vessel a PCI g PC13 g Cl g Kp us 3 1 4 2 2 1 4 1 1 Medica Div

2 49 L of CO2 is passed into excess of lime water solution at 1 bar and 27 C The precipitate is filtered and dried and dissolved in 1 L of 0 2 M HCI solution and heated slightly What is the osmotic pressure of the resulting solution at 27 C R 0 083 L bar K 1 mol Assuming all CO in reaction 1 has been converted into ppt and all CO from reaction 2 escaped into atmoshere

The density of dry air at p 1 1 bar and T 300 K is 1 21 kg m 3 Assuming that it consists entirely of N and O and using the idea gas law determine the amount of each gas in moles and their mole fractions in a volume of 1 m

The Arrhenius activation energy for the following reaction is 15 5 kJ mol What is the value of AH The reaction is H g Br g HBr g Br g A 1 13 kJ mol B 7 19 J mol C 7 19 kJ mol D 1 13 kJ mol

1 The vapour pressure of pure benzene at a certain temperature is 640 mm Hg A non volati non electrolyte solid weighing 2 175 g is added to 39 0 g of benzene The vapour pressure of the solution 600 mm Hg What is the molecular weight of the solid substance in terms of atomic mass unit

A mixture of two immiscible liquids nitrobenzene and wat er boiling at 97 C has a partial vapor pressure of water 73 3 mm and that of nitrobenzene 27 mm The ratio of the we ights of water to nitrobenzene in the distillate is

18 Freundlich adsorption isotherm is represented at temperatures T T and T3 x m T Arrange the temperatures shown in the graph a T T T3 C T T3 T T2 T3 p in the increasing order as b T3 T T d T3 T T 2

A flask contains hydrogen and helium gases in the ratio 1 2 at temperature 300 K The ratio of masses of helium and hydrogen molecules is 2 1 What is the ratio of average translational kinetic energies of these molecules at 500 K 1 3 5 2 5 3 3 2 1

suby Column I On decomposition 50 increase in volume at the pressure On decomposition 100 increase in volume at same temperature and pressure On decomposition no change in volume at the same temperature and pressure d Gases highly soluble in water PA Column II PNH q HI 03 S COCI

D 11 2 L of helium at N T P 38 If NA is Avogadro s number then the number of oxygen atom in one g equivalent of oxygen is B NA 2 D 2 NA 9 Which of the following represents 1 g molecule A NA C NA 4 47 If H to

a 0 124 nm b 0 136 nm c 0 149 nm d 0 110 pm 39 The density of krypton face centered cubic cell is 3 19 g cm What is the radius of the atom Atomic mass Kr 84 a 0 198 nm b 0 221 nm c 0 206 nm d 0 225 nm 40 The face centered cubic cell of platinum has an edge length of 0 392 nm Calculate the density

a 6 80 b 7 60 c 6 60 7 23 2 An element crystallizes in a face centered cubic lattice and the edge of the unit cell is 0 559 nm The density is 3 19 g cm What is the atomic mass a 87 6 b 79 9 c 85 5 83 9

2 mol water is taken into 8 21 L vessel at 300 K Amount of water present in vapour when vapour pressure of water at 300 K is 0 05 atm is Assume the volume taken by H 0 1 as negligible A B C 0 1 g 0 2 g 0 3 g

10 ml of a gaseous mixture containing C H and C H exactly requires 40 ml O for complete combustion and produces 25 ml CO and 30 ml H O vapour The correct information s is are A Total volume contraction 5 ml B Volume contraction due to combustion of C H 0 C x 4 D Volume of CH in the initial mixture 5 ml

Following represents equation of state for n moles of real gas 0 a is expressed in atmL mol 2 b is expressed in Lmol 0 At high pressure compression factor z is Constant a is a measure of force of attraction among gas molecules and n a V Pb RT n a V V nb nRT Select correct statements is called pressure correction term Volume correction is due to finite size of molecules and pressure correction is due to force of attraction between molecules

pH of 0 1 M HA solution is 1 70 and pH of 0 2 M HB solution is 1 00 at 25 C Here HA and HB are weak monobasic acids Value of 10 HB Take log10 2 0 30 Here HA and HB are osmotic pressures of the solution of HA and HB respectively is

21 KMnO4 can be prepared from K MnO4 as per the reaction 3MnO2 2H O 2MnO4 MnO 40H 4 obnolio The reaction can go to completion by removing OH ions by adding NEET 2013 1 KOH 3 SQ noliuloa ispit ed 2 CO 4 HCI

a Describe an activity to prove that liquid pressure at the bottom of a container depends upon the height of the water column above that point Also draw the related diagram b Write the effects of force in the following cases 1 squeezing a rubber ball between palms by applying the same force from both sides 2 a batsman hitting a cricket ball for a six

wo different solutions A and B are separated using a semi permeable membrane as shown in the figure Solution A is 0 2 molarK 4 Fe CN 6 wh solution B is 0 1 molar K SO4 How much pressure in atm must be exerted over surface of one of the solution to prevent any change in their volume due to osmotic flow of water at 300 Kelvin Take R 0 0821 atm L mol k Pair 1 atm Par 1 atm

alculations A student neglected to keep the end of the delivery tube under the surface of the water displaced by hydrogen while the collected gas was cooling What effect will this have on the volume of hydrogen collected What effect will this have on the calculated mass of magnesium

Q 32 Compressibility factor Z of a gas is given as Z pV nRT i What is the value of Z for an ideal gas ii For real gas what will be the effect on value of Z above Boyle temperature Ans i For ideal gas compressibility factor Z 1 ii Above Boyle s temperature real gases show positive deviation Z 10 emulov So 9191020 15

m For the adsorption of a substance M from aqueous solution by charcoal at room temperature the Freundlich constants are n 3 and k 0 5 for in g g and C in g l What is the weight in g of M that will be adsorbed by 2 g of charcoal from 1 litre of solution containing 2 g of the substance originally Report your answer to the nearest integer

A glass cylinder 10 cm in diameter and 20 cm tall initially contains water vapor at 300 K and a pressure of 100 torr A liquid nitrogen cold finger 1 cm in diameter is placed against one face of the cylinder How long will it take for the pressure in the cylinder to drop to 10 5 torr

me gram of a metallic chloride was found to contain 0 835 g of chlorine Its vapour density is 5 If its molecular formula is M CI then what is value of x y 875 g of crystalline barium hydroxide is dissolved in water For the neutralization of this ution 20 mL of N 4 HNO3 is required How many moles of water of crystallization are sent in one mole of this base Given Atomic mass Ba 137 0 16 N 14 H 1 M g of polybasic organic acid Molecular mass 600 required 100 mL of a NaOH solution 6 complete neutralisation Find the basicity of acid mixture contains 10 mole each of NaOH Na CO3 and NaHCO3 When half of mixture is ated with HCl it required x mole of HCl in presence

Kerala PMT 2002 Isothermic nature Solute solute interaction Solute solvent interaction Density of the liquid Incorrect Correct

yind massless piston assembly in which ideal gas is filled Cross sectional area of the cylinder 1m Three masses m m and m3 are kept on the piston When m is removed piston moves upto point A When m1 and m both are removed piston moves upto point B and when m m and M3 all the three are removed piston moves upto point C The work done by the gas is when piston moves from point B to point C Given m 2 x 10 kg m 3 x 10 kg 8 10 m s 2 P 105 Pa atm m m m3 in dng P 106 Pa B FA 20

0 3 Marks Calculate partial pressure of O2 if the density of a mixture of O2 and N is 1 3 gL at STP 1 A B O D 0 5 0 25 0 42 0 28 6 150 Explanation EASY

If 10 dm of water is introduced into a 1 0 dm flask at 300 K how many moles of water are in the vapour phase when equilibrium is established Given Vapour pressure of H O at 300 K is 3170 Pa R 8 314 JK mol a 5 56 10 mol c 4 46 10 2 mol b 1 53 x 10 2 mol d 1 27 10 3 mol