UNIT#03 GASES Flashcards
1
Q
At constant temperature when the pressure of a gas is increased three times then its volume becomes:
A
V/3
(P ∝ 1/V)
2
Q
Under what conditions the density of an ideal gas will be maximum at:
A
➡Low temperature
➡High Pressure
(d= PV/RT)
3
Q
If 1/V is plotted on x-axis and pressure on Y-axis at constant temperature, what should appear:
A
Straight line passing thorugh origin
4
Q
The general gas equation to know the volumes of the gas at various temperatures is:
A
Vt = V° (1+t/273)
5
Q
A mono-atomic substance can store energy only in the form of:
A
Translational Motion
6
Q
A graph between pressure and product of pressure and volume at constant temperature and number of moles is:
A
Straight line parallel to x-axis
7
Q
If both temperature and volme of a gas are doubled, the pressure
A
Remain unchanged
8
Q
WHich one is the form of general gas equation:
A
➡PV=nRT
➡PV=RT
➡P1V1/T1 = P2V2/T2
9
Q
Volume of a gas at S.T.P is 10dm3 at what temperature its volume will become 30dm3, keeping pressure constantWhich of the follwoing pairs of gases possess equal volume at S.T.P
A
819K
(V1T1 = V2T2)
10
Q
Which of the follwoing pairs of gases possess equal volume at S.T.P
A
0.5 mole of NO and 16g of O2
(Equal volume of all ideal gas at same temperature and pressure contain equal number of molecules and moles)
11
Q
Which is incorrect about ideal gas
A
➡No force of attraction between molecules❌
➡No example in nature❌
➡Can be liquified easily✅
➡Obey gas laws at all conditions of temperature and pressure❌
12
Q
A gas initially at 27 °C is heated up to 327 °C, its average kinetic energy will be:
A
Double
13
Q
The coorect value for geenral gas constant is:
A
8.314 x 10^7 erg mol-1 K-1
14
Q
In gases and liquids, temperature is the measure of _____ kinetic energies of molecules.
A
Average translational
15
Q
The molar volume of nitrogen gas is maximum at:
A
130 °C and 1 atm
16
Q
8g of methane and 2g of hydrogen are mixed and kept at 760 mm pressure at 273K, the total volume occupied by the mixture will be:
A
33.6 dm3
17
Q
What is NOT true about gases:
A
➡They are highly compressible❌
➡They have only vibrational motion✅
➡Sudden expansion of gases cause cooling❌
➡They exert pressure on the walls of the vessel❌
18
Q
For a definite mass of ideal gas at constant temperature, the plot of which pair of species will give a curved graph.
A
P vs V
19
Q
A pressure of 0.101325 bar when expressed in atmosphere represents:
A
0.1 atm
(1 atm = 1.10325 bar)
20
Q
Dimensons of the pressure are the same as that of:
A
Force per unit volume
21
Q
Gases deviate from ideal behaviour at high pressure. Which of the following is correct for non-ideality?
A
At high pressure, the volume of the gas becomes insignificant
22
Q
Under high pressure which of the following gas show more ideality in character:
A
N2
Ideality of gas will be more:
➡Less Intermolcular Force
➡Smaller Size
➡Non-Polar
➡Smaller mass
23
Q
When 200cm3 of a gas at constant pressure is heated, its volume:
A
Increases
(V ∝ T)
24
Q
The product of PV of a gas has unit of:
A
Work
(Joule)
25
Under what condition if temperature and pressure will a real gas behave most like an ideal gas?
➡High Temperature
➡Low Pressure
26
Absolute temperature of a gas is direclty proportional to average ___.
Translational Kinetic Energy
27
An ideal gas cant be liquefied because:
Forces between its molecuels are negligible
28
The compressibility factor 'Z' for an ideal gas is:
Equal to one
29
In dm3 atm K-1 mol-1, 2.0 g of hydrogen gas is heated from 27 °C to 327 °C. Which of the following is incorrect
The number of moles of the gas increases
(closed container)
30
A pressure of a gas is due to:
Molecular impacts against the walls of vessel
31
The compressiiblity actor, Z i.e the extent to which a real gas deviated from ideal behaviour is given by:
Z= PV/RT
32
Which of the following gases has the lowest r.m.s velocity at 25 °C
Cl2
33
Value of a ideal gas constant R does not depend upon:
Units of Temperature
34
"a" is called co-efficient of attraction in Van der Waal's equation for real gases the unit of "a" is:
Nm+4/mol2
35
What will be the new volume if temperature and pressure both are reduced to half
Remains same
36
Very small values of Van der Waal's constant in his equation for a particular gas shows that:
Least attractive forces are present among the molecules of the gas
37
Excluded volume is ____ times the actual volume of gas molecules
Four
(b=4Vm)
38
The constant 'a' in Van Der Waal's equation is maximum for:
(a=attraction per unit volume)
Ammonia
(Ammonia has hydrogen bonding, Strong intermolecular force)
39
The average kinetic energy of the gas molecules is:
Directly proprotional to its absolute temperature
40
All the collisions between the particles o gases are elastic in nature. What is meant by "elastic collision"
No change in the kinetic energy
41
Which one of the following expression represent the Avogadro law?
V=RnT/P
(When T and P are constant)
42
The root mean square velocity of gases is inversely proportional to square root of their:
Molar mass
c (r.m.s) = √3RT/M
43
The number of molecules in 22.4 dm3 of H2 gas at 0 °C and 1 atm are:
6.02 x 10^23
44
There are four gases H2, N2, He, and CO2 at 0°C. Which gas shown greater non-ideal.
CO2
(Mass ∝ Intermolecular Force ∝ Non-Ideal Behaviour)
45
Identify the value of R at STP:
0.0821 atm dm3 K-1 mole-1
46
In the Van Der Waals equation, "b" represents that:
Excluded volume per mole
47
Gas is enclosed in a container of 20cm3 with the moving piston. According to kinetic theory o gases, what is the effect on freely moving molecules of the gas if temperature is increased from 20°C to 100°C?Which of the following is the correct equation to calculate relative molecular mass of a gas:
Volume will be increased
(At constant pressure, by increasing temperature volume of a gas molecules)
48
Which of the following is the correct equation to calculate relative molecular mass of a gas:
M = mRT/PV
49
Which of the statmeent is applicable for both ideal and real gases molecules?
➡Have no forces of attraction❌
➡Collisions between the molecules is elastic❌
➡Molecules are in random motion✅
➡The actual volume of gas is negligible as compared to the volume of the gas❌
50
At absolute zero the molecules of hydrogen gas will have:
All the motion are ceased
51
According to the general gas euation, density of an ideal gas depends upon:
➡Pressure
➡Temperature
➡Molar mass of the gas
➡All of the above✅
52
The actual volume of gas molecules is considered neglegibile at following pressures.
2 atm
53
The unit is ___ commonly used by meterologist
Millibar
54
Plasma is difficult to maintain at:
Low Temperature
55
Effusion is the movement of a gas through extremely small opening of molecular size into region of ____ pressure.
Low
56
PV/nRT for an ideal gas is called
Compressibility Factor
57
The sum of moel fraction of the gases in a mixture of gases is:
Always 1
58
According to Avogadro's law, .889 g of 1dm3 H2 and 1.4384g of 1 dm3 O2 have number of molecules
Same
59
Calculate the mass of 1dm3 of NH3 gas at 3°C and 1mm Hg pressure, considering that NH3 is ideally behaving
0.99 g
60
212-degree Farhenheit is expressed Kelvin as:
373
61
For non-ideal gas:
PV/NRT is not equal to Z
62
R does not depend upon:
Pressure
63
Which law is applicable while respiration:
Dalton's Law
64
Which has the highest rate of diffusion:
NH3SO2
65
Effusions are:
Inversely to the square root of mass
66
KMT is discovered by:
Bernoulli
67
Which of these gases cannot liquify:
➡H2
➡He
68
The general gas equation is also known as:
Ideal
69
When temperature increases, the isotherm moves:
Away from both axis
70
Volume in an ideal gas is directly related to;
➡n
➡T
➡P
71
According to kinetic molecular theory absolute temperature is directly proportional to ___ of molecules.
Average translational kinetic Energy
72
Calculate the density of methane in g/L at -450°C and 300 torr pressure.
0.338
73
The general gas equation is also known as;
Ideal gas equation
74
The general gas equation is used for;
Ideal gas
75
General Gas Equation
PV=nRT
76
Liquids have no definite shape it is because
The molecules of liquid are in constant motion by sliding over each other
77
A class of materials with highly variable mechanical and optical properties that solidify from the molten state without crystallization are called
Amorphous solids
78
Gases deviate from Ideal behaviour at high pressure. Which of the following is correct for non idealty
At high pressure, the intermolecular attractions become significant
79
Under high pressure which of the following gas show more ideality in character
N2
CO2
NH3
SO2
N2
80
Absolute zero is
-459.67°F
81
The correct value of general gas constant is
8.314×10⁷ erg/mol.K
82
An ideal gas can't be liquefied because
Forces between its molecules are negligible
83
A fire extinguisher delivers 2.2 kg of CO2. volume of CO2 at STP is
1120 dm3
84
When 200 ml of a gas at constant pressure is hated its volume
Increases
85
The product of PV of a gas is a unit of
Work
86
Gases exert pressure on the walls of the container because the gas molecules
Collide with walls of container
87
Which one of the following is absolute zeroThe number of molecules in 0.0112m3 of Methane at 0°C and pressure of 760 mm Hg is
Zero kelvin
88
The number of molecules in 0.0112m3 of Methane at 0°C and pressure of 760 mm Hg is
3.01×10^23
89
Which of the following will have same number of molecules at STP
280 cm3 of CO2 and 280 cm3 of N2O
90
The graph between pressure and inverse of volume at constant pressure and number of moles
Straight line passing through the origin
91
In a closed vessel of 1000 cm3, H2 gas is heated from 27°C to 127°C. Which statement is not correct
The number of moles of gas increases
92
The molecules of gas show more deviation from Ideal behaviour at low temperature because
Attractive force dominate at low temperature
93
The gas was our best applicable under the condition
Low pressure and high temperature
94
The root mean square velocity is expressed as
(3RT/M)½
95
At constant pressure volume of given mass of gas is directly proportional to
Absolute Temperature
96
Absolute zero is unattainable temperature, current attempts have resulted in the lowest temperature of
10–⁵ K
97
If temperature is increasing continuously then constant k in PV=k will
Increase
98
What will happen to density of an ideal gas if both temperature and pressure are doubled
Remain same
99
100m³ of a gas at 3atm and 27°C is transferred into a container having volume 300 m³ and temperature 327°C. Pressure in new container will be
2 atm
100
Value of general gas constant R depends on
Units of P and V
101
Which of the molecules have maximum root mean square velocity at 25°C
NH3
102
Which of the following gas show maximum ideal behaviour
N2
103
The density of Methane at 2atm pressure at 27°C is
1.3 gdm-3
104
The correct mathematical form of Avogadro's law is
V1\V2=n1\n2
105
The deviation of gas from Ideal behaviour is maximum at
-10°C and 5atm
106
If Absolute Temperature is doubled and the pressure is increased to four times, the volume of gas is
Half
107
The average kinetic energy of gas molecules is
Directly proportional to its Absolute Temperature
108
The compressibility factor Z for an ideal gas is
Equal to 1
109
If we increase or decrease the amount of heat to a liquid, its boiling point will
Remain constant
110
Which is the correct order of boiling points
H2O >HF >NH3 >CH4
111
Evaporation of water depends upon
Surface area and intermolecular forces
speed of air above the liquid surface
humidity in air
112
110°C boiling point of water corresponds to the external pressure
Between 760 to1200 torr
113
Boiling point of compound is mostly raised by
Intermolecular hydrogen bonding
114
Which has greater enthalpy of vaporization
I2 (iodine)
115
Identify incorrect statement about evaporation
Exothermic
116
Which mathematical relationship doesn't correctly represent behaviour of an ideal gas
Pressure is inversely proportional to density
117
Maximum vapour pressure is shown by
50 cm3 ethanol and 1dm3 ethanol
118
Evaporation occurs at
All temperatures
119
Which one is the most accurate method for the measurement of vapour pressure
Manometric method
120
The vapour pressure of methanol at 40°C is less than
Ether
121
The volume of a given mass of gas is _____ to the inverse of the pressure
Direclty Proprotional
122
At constant temperature, by doubling the pressure volume of gas reduced to _____.
1/2 of original volume
123
Gases aresoluble in water at:
➡Low Temperature
➡High Pressure
124
The SI Unit of pressure is Nm-3. 10^03 atm is equal to:
0.101325 KPa
125
Which one has more mass at STP
1 dm^3 of O2
126
Two gases having same temperature and pressure will have:
➡Same volume
➡Same no. of molecules
➡Same moles
127
For a given mass with initial volume "V", if pressure is reduced t one half and absolute temperature is increasesd two times. The volume will become;
4V
128
Which of the following expressions at constant pressure represents Charles's law
V` ∝ T
129
Which of the following relation is true for the density of an ideal gas
PM/RT
130
If absolute temperature and pressure of gas is doubled then volume o gas will:
Remain unchanged
131
The expression for root mean square velocity is:
c(r.m.s) = √3/2RT/M
132
16g of each of CH4 and He are in a container at 50°C. The ratio of kinetic energy is:
1:4
133
According to kinetic molceular theory the kinetic energy of gas molecules varies directly with:
Absolute Temperature
134
Which of the following is NOT the basic assumption of the kinetic theory of gases:
➡The collisions among the molecule of the gas are perfectly elastic❌
➡The molecules of the gas are always in the state of ceaseless haphhazard motion❌
➡The pressure of a gas is due to collision of gas molecules with the walls of container❌
➡The molecules exert appreciable attraction on each other✅
135
In gases, Temperature is the measure of;
Average translational Kinetic Energy
136
Observed pressure of gas on the walls of container is less than actual pressure due to:
Inter molecular attractive forces
137
A gas that has highest value for Van der Waals coefficient of attraction
NH3
138
A gas under what conditions will behave non-ideally:
➡Temperature: Low
➡Pressure; High
(At low temperature and high pressure intermolecular forces develop significantly)
139
Gases deviate from ideal behaviour at high pressure. Which of the following is correct for non-ideality?
At high pressure, the intermolecular attraction become significant
140
Which of the following shows strange behaviour when subjected to gradual increase in pressure at 0°C
CO2
141
In Boyles law, plot between pressure and constant 'K' obtained is::
Straight Line parallel to pressure axis
142
If volume of O2 is 11.2dm3 at STP, then the number of moles would be:
0.5 moles
143
Pressure remaining constant at which temperature the volume of gas will become twice of what it is at 0°C
546K
144
If temperature of 1 mole of gas is raised by 1K, then it would absorb ____ amount of energy.
0.0821 dm3 atm
145
When the value of general gas constant 'R' us given as 8.314. The relevant units will be;
J. mol-1. K-1
146
In the ideal gas equation PV = nRT, the value of R depends upon:
Units of measurement
147
The gas having highest density is:
Cl2
148
According to Kinetic theory of gases which relation is correct:
PV = 2/3 kT
149
The molecular velocity of a gas is:
Proportional to root mean square velocity of a gas
150
The root mean square velocity is equivalent to:
➡C (r.m.s) = √3RT/M
➡C (r.m.s) = √3PV/M
➡C (r.m.s) = √3P/d
151
If the temperature of a gas is increased four times then its average K.E.
Increases 4 times
152
All of the following equations are expression for the ideal gas law:
➡PV = nRT
➡PV/T = constant
➡P1V1/T1 = P2V2/T2
153
Real gases show more deviation from ideal behaviour under which of the following conditions:
➡at low temperature
➡high pressure
154
In Van der Waal's equation, if the value of 'a' and 'b' are zero for a certain gas, then the gas is:
Ideal
155
Real gases deviate at low temperature from ideal behaviour due to;
Significant increase in the intermolecular attractive forces
156
Effective volume of molecules per mole of a gas is ____ times greater than actual volume of 1 mole of gas molecules
4
157
The compressibility factor, (Z=PV/nRT) has value at which a gas show maximum non-ideality in behaviour:
1.5
(Greater the value of 'Z', greater the real behaviour)
158
Gases exert pressure on the walls of the container because the gas molecules:
Collide with the walls of the container
159
Which one of the following is absolute zero
0 K
160
Crystalline solids are classified on the basis of bonding into ___ types.
Four
161
The number of molecules in 0.0112 m^3 of methane at 0°C and pressure of 760 mm Hg is:
3.01 x 10^23
162
Which of the following will gave the same number of molecules at STP
280 cm^3 of CO2 and 280 cm^3 of N2O
163
The graph between pressure and inverse of volume at constant temperature and number of moles
A straight line passing through the origin
164
In a closed vessel of 1000 cm^3, H2 gas is heated from 27°C to 127°C. Which statement is correct?
The number of moles of gas increases
165
The molecules of gas show more deviation from ideal behaviour at low temperatures, because;
Attractive force dominates at low temperature
166
The gas laws are best applicable under the conditions:
➡Low P
➡High T
167
The root means square velocity is expressed as:
(3RT/M)^1/2
168
At constant pressure, the volume of a given mass of a gas is directly proportional to;
Absolute temperature
169
Absolute zero is an unattainable temperature, current attempts have resulted in the lowest of:
10^-5 K
170
If the temperature is increasing continuously then constant 'k' in PV=k will;
Increase
171
What will happen to the density of an ideal gas, if both temperature and pressure are doubled;
Remain same
172
100 m^3 of gas at 3atm and 27°C is transferred into a container having a volume of 300 m^3 and a temperature of 327°C. Pressure in the new container will be;
2 atm
173
The value of the general gas constant 'R' depends upon;
Units of P and V
174
Which of the following molecules has a maximum root mean square velocity at 25°C?
NH3
175
Which of the following gas show maximum ideal behaviour
N2
176
Which mathematical relationship doesn't correctly represent the behaviour of an ideal gas
P ∝ 1/d
177
The density of methane at 2 atm pressure at 27°C is;
1.3 g/dm^3
178
The correct mathematical form of Avogadro's law is:
V1/V2 = n1/n2
179
Which one is most real at STP:
NH3
180
The deviation of gas from ideal behaviour is maximum at:
-10°C and 5.0 atm
(At low temperatures or high pressures, real gases deviate significantly from ideal gas behaviour)
181
If the absolute temperature is doubled and the pressure is increased to 4 times, the volume of gas is;
Half
182
The average K.E of the gas molecules is;
Directly proportional to its absolute temperature
183
The compressibility factor (Z) for an ideal gas is;
Equal to one
184
At constant pressure, the volume of a given mass of a gas is directly proportional to;
Temperature
185
The volume of a gas at S.T.P is 10 dm^3 at which temperature its volume will become 30 dm^3, keeping the pressure constant
819 K
186
Absolute zero is an unattainable temperature, current attempts have resulted in the lowest temperature of;
10^-5 K
187
Which of the following pairs of gases possess equal volume at STP
➡0.5 moles of NO
➡16 g O2
188
Which of the following pairs have the same rates of diffusion;
➡N2O
➡CO2
189
Units of PV are the same as that of;
Energy
190
If the temperature is increasing continuously then constant 'K' in PV=K will;
Increase
191
What will happen to the density of an ideal gas, if both temperature and pressure are doubled;
Remain same
192
Absolute zero is;
-459.4°F
193
A gas initially at 27°C is heated up to 327°C, and its average K.E will be;
Doubled
194
100m^3 of a gas at 3 atm and 27°C is transferred into a container having a volume of 300m^3 with a temperature of 327°C. Pressure in new container will ber:
2 atm
195
Value of general gas constant 'R" depends upon:
Units of P and V
196
The correct value of general gas constant R is;
8.314 x 10^7 erg mol^-1
197
The absolute temperature of a gas is directly proportional to the average;
Translational kinetic energy
198
Which pair of gases do not obey Dalton's law of partial pressure;
➡NH3
➡HCl
199
The ratio of the rate of diffusion of equal volumes of He and SO2 is:
4:1
200
NH3 gas diffuses twice faster than the gas;
C5H8
201
At the same temperature and pressure, two balloons are separately filled with H2 and O2. If O2 escapes at the rate of 60 cm/hr, the rate of diffusion of hydrogen will be:
240 cm/hr
202
Which of the following molecules has a maximum root mean square velocity at 25°C
NH3
203
Two balloons are filled with equal moles of H2 and He at STP. Which balloon will contract first if the same size holes are made in both of them?
Ballon filled with H2
204
An ideal gas can't be liquified because;
Forces between its molecules are negligible
205
Which of the following gas show maximum ideal behaviour
N2
206
The SI unit of 'a' is:
Nm^4mol^-2
207
The least values of Van der Waal's constants 'a' and 'b' are for:
Hydrogen
208
Which mathematical relationship doesn't correctly represent the behaviour of an ideal gas?
➡P ∝ CT❌
➡P ∝ dT❌
➡P ∝ 1/d✅
209
Which statement is correct regarding Van Der Waal's equation:
a NH3 > a N2 > and b NH3 > b N2
210
A fire extinguisher delivers 2.2 kg of CO2. The volume of CO2 at STP is;
1120 dm^3
211
The ratio of partial pressure of helium to the hydrogen in a mixture of 4g o hydrogen and 4g of helium is:
1/2
212
A mixture of 64g each of SO2, O3, O2 and CH4 is taken in a cylinder, the correct order of their partial pressure is:
CH4>O2>O3>SO2
(Partial Pressure ∝ No. of moles ∝ m/M)
213
The number of molecules in 0.0112 m^3 of methane at 0°C and pressure 760mmHg is:
3.01 x 10^23
214
Which of the following will have the same number of molecules at STP
➡280 cm^3 of CO2
➡280 cm^3 of N2O
215
The partial pressure of oxygen in the lungs is;
116 torr
216
Gases deviate from ideal behaviour at high pressure. Which of the following is correct for non-ideality:
At high pressure, the inter-molecular attractions become insignificant
217
Evaporation is designated as a cooling process because of the reason:
High energy molecules leave behind the low energy molecules and cause cooling
218
Evaporating water depends upon the following;
➡Surface area and intermolecular forces
➡Speed of the air above the liquid surface
➡Humidity of air
219
The graph between and inverse of volume at constant temperature and number of moles;
A straight line passing through the origin
220
If both the temperature and volume of a gas are doubled, the pressure
Remain unchanged
221
In a closed vessel of 1000 cm^3, H2 gas is heated from 27°C to 127°C. Which statement is not correct?
➡The rate of collision increases❌
➡Pressure of gas increases❌
➡The energy of gas molecules increases❌
➡The number of moles of gas ✅
222
Which one is the form of a general gas equation:
➡PV=nRT
➡PV=RT
➡P1V1/T1 = P2V2/T2
223
The sudden expansion of the gas from high pressure towards the low-pressure causes:
Decrease in temperature
224
The molecules of gas show more deviation from ideal behaviour at low temperatures, because
Attractive forces dominate at low temperature
225
Which of the following temperature scale can not have a negative value:
Kelvin
226
The gas laws are best applicable under the conditions;
➡Low P
➡High T
227
Under high pressure which of the following gas show more ideality in character
N2
228
Which is incorrect about ideal gas?
➡No force of attraction between molecules❌
➡No example in nature❌
➡Can be liquefied easily❌
➡Obey gas laws under all conditions of temperature and pressure✅
229
Gases exert pressure on the walls of containers because the gas molecules:
Collide with the walls of the container
