Tiêu đề 13. KINETIC THEORY - Questions.pdf ✅

13. KINETIC THEORY (1.)A sample of gas is at 0°C. To what temperature it must be raised in order to double the r. m. s. speed of the molecule (a.) 270°C (b.) 819°C (c.) 1090°C (d.) 100°C (2.)The rate of cooling at 600 K, if surrounding temperature is 300 K isR. The rate of cooling at 900 K is (a.) 16 3 R (b.) 2 R (c.) 3 R (d.) 2 3 R (3.)One kg of a diatomic gas is at a pressure of 8 × 104 Nm−2 . The density of the gas is 4 kgm−3 . What is the energy of the gas due to its thermal motion? (a.) 3 × 104 J (b.) 5 × 104 J (c.) 6 × 104 J (d.) 7 × 104 J (4.)At constant volume the specific heat of a gas is 3R 2 , then the value of ′γ′ will be (a.) 3 2 (b.) 5 2 (c.) 5 3 (d.) None of the above (5.)A gas is filled in a cylinder, its temperature is increased by 20% on kelvin scale and volume is reduced by 10%. How much percentage of the gas will leak out (a.) 30% (b.) 40% (c.) 15% (d.) 25% (6.)The figure shows the volume V versus temperature T graphs for a certain mass of a perfect gas at two constant pressures of P1 and P2. What inference can you draw from the graphs (a.) P1 > P2 (b.) P1 < P2 (c.) P1 = P2 (d.) No interference can be drawn due to insufficient information (7.)The root mean square speed of the molecules of a gas is (a.) Independent of its pressure but directly proportional to its Kelvin temperature (b.) Directly proportional to the square roots of both its pressure and its Kelvin temperature (c.) Independent of its pressure but directly proportional to the square root of its Kelvin temperature (d.) Directly proportional to both its pressure and its kelvin temperature (8.)In the absence of intermolecular forces of attraction, the observed pressure p will be (a.) p (b.) < p (c.) > p (d.) Zero (9.)A gas mixture consists of 2 moles of oxygen and 4 moles of argon at temperature T. Neglecting all vibrational moles, the total internal energy of the system is (a.) 4 RT (b.) 15 RT (c.) 9 RT (d.) 11 RT (10.)In Vander Waal’s equation a and b represent (P + a V2 ) (V − b) = RT (a.) Both a and b represent correction in volume (b.) Both a and b represent adhesive force between molecules (c.) a represents adhesive force between molecules and b correction in volume (d.) a represents correction in volume and b represents adhesive force between molecules (11.)The temperature gradient in the earth’s crust is 32°C km−1 and the mean conductivity of earth is 0.008 cals −1 cm−1°C−1 . Considering earth to be a sphere of radius 6000 km loss of heat by earth everyday is about (a.) 1030 cal (b.) 1040 cal (c.) 1020 cal (d.) 1018 cal (12.)Two moles of oxygen is mixed with eight moles of helium. The effective specific heat of the mixture at constant volume is V T 1 P1 P2 2
(a.) 1.3 R (b.) 1.4 R (c.) 1.7 R (d.) 1.9 R (13.)If γ is the ratio of specific heats and R is the universal gas constant, then the molar specific heat at constant volume Cv is given by (a.) γR (b.) (γ−1)R γ (c.) R γ−1 (d.) γR γ−1 (14.)According to the kinetic theory of gases the r. m. s. velocity of gas molecules is directly proportional to (a.) T (b.) √T (c.) T 2 (d.) 1/√T (15.)If mass of He is 4 times that of hydrogen, then mean velocity of He is (a.) 2 times of H-mean value (b.) 1 2 times of H-mean value (c.) 4 times of H-mean value (d.) Same as H-mean value (16.)The relationship between pressure and the density of a gas expressed by Boyle’s law, P = KD holds true (a.) For any gas under any conditions (b.) For some gases under any conditions (c.) Only if the temperature is kept constant (d.) Only if the density is constant (17.)Two different masses m and 3m of an ideal gas are heated separately in a vessel of constant volume, the pressure P and absolute temperature T, graphs for these two cases are shown in the figure as A and B. The ratio of slopes of curves B to A is (a.) 3 ∶ 1 (b.) 1 ∶ 3 (c.) 9 ∶ 1 (d.) 1 ∶ 9 (18.)Read the given statements and decide which is/are correct on the basis of kinetic theory of gases (I) Energy of one molecule at absolute temperature is zero (II) r. m. s. speeds of different gases are same at same temperature (III) For one gram of all ideal gas kinetic energy is same at same temperature (IV) For one mole of all ideal gases mean kinetic energy is same at same temperature (a.) All are correct (b.) I and IV are correct (c.) IV is correct (d.) None of these (19.)Air is filled in a bottle at atmospheric pressure and it is corked at 35°C. If the cork can come out at 3 atmospheric pressure than upto what temperature should the bottle be heated in order to remove the cork (a.) 325.5°C (b.) 851°C (c.) 651°C (d.) None of these (20.)The temperature of an ideal gas is increased from 27°C to 127°C, then percentage increase in Vrms is (a.) 37% (b.) 11% (c.) 33% (d.) 15.5% (21.)Pressure versus temperature graph of an ideal gas at constant volume V of an ideal gas is shown by the straight line A. Now mass of the gas is doubled and the volume is halved, then the corresponding pressure versus temperature graph will be shown by the line (a.) A (b.) B (c.) C (d.) None of these (22.)Two spheres made of same substance have diameters in the ratio1 ∶ 2. Their thermal capacities are in the ratio of (a.) 1 : 2 (b.) 1 : 8 (c.) 1 : 4 (d.) 2 : 1 (23.)Boyle’s law holds for an ideal gas during (a.) Isobaric changes (b.) Isothermal changes (c.) Isochoric changes (d.) Isotonic changes (24.)If the rms velocity of a gas is v ,then P T m B 3m A P T C B A
(a.) v 2T = constant (b.) v 2⁄T = constant (c.) vT 2 = constant (d.) v is independent of T (25.)The ratio of root mean square velocity of O3 and O2 is (a.) 1: 1 (b. ) 2: 3 (c.) 3: 2 (d. ) √2 ∶ √3 (26.)22 g of carbon dioxide at 27°C is mixed in a closed container with 16 g of oxygen at 37°C. If both gases are considered as ideal gases, then the temperature of the mixture is (a.) 24.2°C (b.) 28.5°C (c.) 31.5°C (d.) 33.5°C (27.)Speed of sound in a gas is v and r. m. s. velocity of the gas molecules is c. The ratio of v to c is (a.) 3 γ (b.) γ 3 (c.) √ 3 γ (d.) √ γ 3 (28.)PV versus T graph of equal masses of H2, He and O2 is shown in fig. Choose the correct alternative (a.) C corresponds to H2, B to He and A to O2 (b.) A corresponds to He, B to H2 and C to O2 (c.) A corresponds to He, B to O2 and C to H2 (d.) A corresponds to O2, B to H2 and C to He (29.)Mean kinetic energy (or average energy) per g molecule of a monoatomic gas is given by (a.) 3 2 RT (b.) 1 2 kT (c.) 1 2 RT (d.) 3 2 kT (30.)On 0°C pressure measured by barometer is 760 mm. What will be pressure at 100°C (a.) 760 mm (b.) 730 mm (c.) 780 mm (d.) None of these (31.)At NTP, sample of equal volume of chlorine and oxygen is taken. Now ratio of no. of molecules is (a.) 1 ∶ 1 (b.) 32 ∶ 27 (c.) 2 ∶ 1 (d.) 16 ∶ 14 (32.)A real gas behaves like an ideal gas if its (a.) Pressure and temperature are both high (b.) Pressure and temperature are both low (c.) Pressure is high and temperature is low (d.) Pressure is low and temperature is high (33.)In the relation n = PV RT , n = (a.) Number of molecules (b.) Atomic number (c.) Mass number (d.) Number of moles (34.)If pressure of CO2 (real gas) in a container is given by P = RT 2V−b − a 4b 2 , then mass of the gas in container is (a.) 11 g (b.) 22 g (c.) 33 g (d.) 44 g (35.)A steel ball of mass 0.1 kg falls freely from a height of 10 m of 10 m and bounces to a height of 5.4 m from the ground. If the dissipated energy in this process is absorbed by the ball, the rise in its temperature is (a.) 0.01°C (b.) 0.1°C (c.) 1.1°C (d.) 1°C (36.)Cooking gas containers are kept in a lorry moving with uniform speed. The temperature of the gas molecules inside will (a.) Increase (b.) Decrease (c.) Remain same (d.) Decrease for some, while increase for others (37.)One mole of an ideal gas requires 207 J heat to raise the temperature by 10 K when heated at constant pressure. If the same gas is heated at constant volume to raise the temperature by the same 10 K, the heat required is (Given the gas constant R = 8.3 J/mol − K) (a.) 198.7 J (b.) 29 J (c.) 215.3 J (d.) 124 J (38.)22 g of CO2 at 27°C is mixed with 16 g of oxygen at 37°C. The temperature of the mixture is (a.) 32°C (b.) 27°C PV T O A C B
(c.) 37°C (d.) 30°C (39.)The power radiated by a black body is P, and it radiates maximum energy around the wavelength λ0. If the temperature of black body is now changed so that it radiates maximum energy around a wavelength λ0/4, the power radiated by it will increase by a factor of (a.) 4 3 (b.) 16 9 (c.) 64 27 (d.) 256 81 (40.)A cylinder of radius r and thermal conductivity K1 is surrounded by a cylindrical shell of linear radius r and outer radius2r, whose thermal conductivity is K2. There is no loss of heat across cylindrical surfaces, when the ends of the combined system are maintained at temperatures T1 and T2. The effective thermal conductivity of the system, in the steady state is (a.) K1K2 K1+K2 (b.) K1 + K2 (c.) K1+3K2 4 (d.) 3K1+K2 4 (41.)At temperature T, the r. m. s. speed of helium molecules is the same as r. m. s. speed of hydrogen molecules at normal temperature and pressure. The value of T is (a.) 273°C (b.) 546°C (c.) 0°C (d.) 136.5°C (42.)Vessel A is filled with hydrogen while vessel B, whose volume is twice that of A, is filled with the same mass of oxygen at the same temperature. The ratio of the mean kinetic energies of hydrogen and oxygen is (a.) 16 ∶ 1 (b.) 1 ∶ 8 (c.) 8 ∶ 1 (d.) 1 ∶ 1 (43.)The average kinetic energy of a helium atom at 30°C is (a.) Less than 1 eV (b.) A few keV (c.) 50 − 60 eV (d.) 13.6 eV (44.)A bubble is at the bottom of the lake of depth h. As the bubble comes to sea level, its radius increases three times. If atmospheric pressure is equal to l metre of water column, then h is equal to (a.) 26 l (b.) l (c.) 25 l (d.) 30 l (45.)The following sets of values for CV and CP of a gas has been reported by different students. The units are cal/g-mole-K. Which of these sets is most reliable (a.) CV = 3, CP = 5 (b.) CV = 4, CP = 6 (c.) CV = 3, CP = 2 (d.) CV = 3, CP = 4.2 (46.)The kinetic energy of one mole gas at 300K temperature, is E. At 400 K temperature kinetic energy is E ′ . The value of E ′ /E is (a.) 1.33 (b.) √( 4 3 ) (c.) 16 9 (d.) 2 (47.)The average translational kinetic energy of a hydrogen gas molecules at NTP will be [Boltzmann’s constant kB = 1.38 × 10−23J/K] (a.) 0.186 × 10−20Joule (b.) 0.372 × 10−20Joule (c.) 0.56 × 10−20Joule (d.) 5.6 × 10−20Joule (48.)The specific heat relation for ideal gas is (a.) CP + CV = R (b.) CP − CV = R (c.) CP/CV = R (d.) CV/CP = R (49.)The kinetic energy per g mol for a diatomic gas at room temperature is (a.) 3 RT (b.) 5 2 RT (c.) 3 2 RT (d.) 1 2 RT (50.)The molar specific heat at constant pressure of an ideal gas is (7/2)R. The ratio of specific heat at constant pressure to that at constant volume is (a.) 5/7 (b.) 9/7 (c.) 7/5 (d.) 8/7 (51.)What is the mass of 2 L of nitrogen at 22.4 atm pressure and 273 K? (a.) 28 g (b.) 14 × 22.4 g (c.) 56 g