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CHM 112 > Chpt 3 Real Or Ideal Gas Behavior > Flashcards

Chpt 3 Real Or Ideal Gas Behavior Flashcards

1
Q

QUESTION

A

OPTION 1

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2
Q
  1. What is the van der Waals equation used to describe? (a) Ideal gas behavior (b) Real gas behavior (c) Ideal and real gas behavior (d) Chemical reactions
A

Answer: b) Real gas behavior

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3
Q
  1. When do both b and a constants in the van der Waals equation become negligible? (a) When pressure is low (b) When temperature is low (c) When pressure is high (d) When temperature is high
A

Answer: d) When temperature is high

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4
Q
  1. What does the term ‘a’ in the van der Waals equation represent? (a) The volume occupied by gas molecules (b) The attractive forces between molecules (c) The total pressure (d) The volume of the gas
A

Answer: b) The attractive forces between molecules

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5
Q
  1. What is the role of the critical temperature of a substance? (a) It is the highest temperature at which gas and liquid can exist as separate phases (b) It is the lowest temperature at which gas can exist (c) It is the temperature at which the gas condenses to a liquid (d) It defines the density of the gas
A

Answer: a) It is the highest temperature at which gas and liquid can exist as separate phases

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6
Q
  1. What does the critical pressure refer to? (a) The pressure at the critical point where gas and liquid phases become indistinguishable (b) The pressure at which gas liquefies (c) The pressure required for a gas to form a vapor (d) The pressure at low temperatures
A

Answer: a) The pressure at the critical point where gas and liquid phases become indistinguishable

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7
Q
  1. At what temperature does the meniscus between gas and liquid phases disappear? (a) At absolute zero (b) At the freezing point (c) At the boiling point (d) At the critical temperature
A

Answer: d) At the critical temperature

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8
Q
  1. Which of the following is true about the critical molar volume? (a) It is the molar volume at standard temperature and pressure (b) It is the molar volume at the critical temperature and pressure (c) It is the volume of gas at high temperatures (d) It is the volume of gas at very low pressures
A

Answer: b) It is the molar volume at the critical temperature and pressure

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9
Q
  1. What happens to the compressibility factor Z when a gas is more compressible than an ideal gas? (a) Z is constant (b) Z > 1 (c) Z = 1 (d) Z < 1
A

Answer: d) Z < 1

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10
Q
  1. What causes the positive deviation from ideal gas behavior in real gases? (a) Intermolecular attraction forces (b) Decreased volume of molecules at low temperature (c) Increased volume of molecules at high pressure (d) No molecular volume
A

Answer: c) Increased volume of molecules at high pressure

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11
Q
  1. In the van der Waals equation, what does the constant b account for? (a) Intermolecular attractive forces (b) Pressure of the gas (c) Volume occupied by gas molecules (d) Temperature of the gas
A

Answer: c) Volume occupied by gas molecules

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12
Q
  1. What happens to the behavior of gases at high pressures and low temperatures? (a) They behave ideally (b) They become more compressible (c) They show significant deviations from ideal gas behavior (d) They follow Boyle’s law perfectly
A

Answer: c) They show significant deviations from ideal gas behavior

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13
Q
  1. What is the importance of the horizontal lines in carbon dioxide isotherms? (a) They show the transition of gas into a vapor (b) They represent the critical point (c) They represent the maximum temperature for a gas (d) They indicate the condensation of gas into liquid
A

Answer: d) They indicate the condensation of gas into liquid

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14
Q
  1. How is the molar volume of a gas affected by intermolecular attractions? (a) It remains constant (b) It decreases with stronger attractions (c) It increases with stronger attractions (d) It is unaffected by intermolecular forces
A

Answer: b) It decreases with stronger attractions

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15
Q
  1. Which of the following gases has a high critical temperature? (a) N₂ (b) CO₂ (c) He (d) H₂O
A

Answer: d) H₂O

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16
Q
  1. What is the equation for the excluded volume in the van der Waals equation? (a) (4/3)πr³ (b) πr² (c) (2/3)πr³ (d) 4πr²
A

Answer: a) (4/3)πr³

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17
Q
  1. What happens in the two-phase region of the pressure-volume diagram near the critical temperature? (a) Only vapor exists (b) Gas phase becomes dominant (c) Liquid phase becomes dominant (d) Gas and liquid phases exist together
A

Answer: d) Gas and liquid phases exist together

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18
Q
  1. What does a gas in equilibrium with its corresponding liquid phase refer to? (a) A supercritical fluid (b) A vapor (c) A pure substance (d) An ideal gas
A

Answer: b) A vapor

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19
Q
  1. What defines the critical state of a substance? (a) The temperature at which gas becomes a solid (b) The point at which the gas condenses (c) The point at which gas and liquid phases become indistinguishable (d) The temperature at which the gas vaporizes
A

Answer: c) The point at which gas and liquid phases become indistinguishable

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20
Q
  1. What is the van der Waals constant ‘a’ related to? (a) The molecular weight of the gas (b) The temperature of the gas (c) The intermolecular attractive forces (d) The volume of molecules
A

Answer: c) The intermolecular attractive forces

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21
Q
  1. Which of the following factors is most important for gas liquefaction at low temperatures? (a) High molecular volume (b) High pressure (c) High temperature (d) Attractive forces between molecules
A

Answer: d) Attractive forces between molecules

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22
Q
  1. What is the significance of the van der Waals equation compared to the ideal gas law? (a) It accounts for molecular volume and intermolecular attraction (b) It assumes ideal gas behavior (c) It simplifies gas behavior at low temperatures (d) It only accounts for temperature
A

Answer: a) It accounts for molecular volume and intermolecular attraction

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23
Q
  1. How is the critical density of a substance obtained? (a) By measuring the volume of the gas at critical pressure (b) By determining the temperature at which gas condenses (c) By plotting average densities of liquid and vapor phases at various temperatures (d) By calculating the molar volume at standard conditions
A

Answer: c) By plotting average densities of liquid and vapor phases at various temperatures

24
Q
  1. What does the van der Waals equation correct for in comparison to the ideal gas law? (a) The mass of gas molecules (b) The ideal behavior of gases (c) The volume occupied by gas molecules and intermolecular forces (d) The temperature dependence of gases
A

Answer: c) The volume occupied by gas molecules and intermolecular forces

25
Q
  1. At what condition do real gases exhibit negative deviations from the ideal gas law? (a) Low pressure and high temperature (b) Low pressure and low temperature (c) High pressure and low temperature (d) High pressure and high temperature
A

Answer: c) High pressure and low temperature

26
Q
  1. What effect does an increase in temperature have on the positive deviation in the compressibility factor? (a) It causes negative deviation (b) It reduces the positive deviation (c) It has no effect (d) It increases the positive deviation
A

Answer: d) It increases the positive deviation

27
Q
  1. What is the nature of gases at temperatures above the critical temperature? (a) They become highly compressed (b) They cannot be liquefied regardless of pressure (c) They exist as vapors (d) They condense into liquid
A

Answer: b) They cannot be liquefied regardless of pressure

28
Q
  1. What happens at the critical point of a gas? (a) The temperature stops increasing (b) The gas solidifies (c) The gas starts to liquefy (d) Gas and liquid phases become indistinguishable
A

Answer: d) Gas and liquid phases become indistinguishable

29
Q
  1. What is the effect of intermolecular forces on the compressibility of a gas? (a) It reduces the compressibility at low temperatures (b) It increases the compressibility (c) It has no effect on the gas (d) It makes the gas behave ideally
A

Answer: a) It reduces the compressibility at low temperatures

30
Q
  1. What is the definition of a vapor in relation to critical temperature? (a) A gas above its critical temperature (b) A gas below its critical temperature (c) A solidified gas (d) A gas at its critical pressure
A

Answer: b) A gas below its critical temperature

31
Q
  1. How does the van der Waals equation improve the prediction of real gas behavior? (a) By ignoring intermolecular forces (b) By simplifying gas behavior at low temperatures (c) By assuming that gases behave ideally (d) By including terms for intermolecular attraction and molecular volume
A

Answer: d) By including terms for intermolecular attraction and molecular volume

32
Q
  1. What does the compressibility factor (Z) express in real gases? (A) The molecular weight of the gas (B) The rate of gas diffusion (C) The deviation from ideal behavior (D) The volume of gas molecules
33
Q
  1. At high pressures and low temperatures, real gases show (A) Appreciable deviations from the ideal gas law (B) Perfect behavior according to the ideal gas law (C) No deviation from ideal behavior (D) Reduced molecular volume
34
Q
  1. In the ideal gas law, PV = nRT, what is the value of Z for an ideal gas? (A) 1 (B) 0 (C) Greater than 1 (D) Less than 1
35
Q
  1. A compressibility factor Z less than 1 indicates that the gas is (A) More compressible than an ideal gas (B) Less compressible than an ideal gas (C) At ideal behavior (D) Not affected by temperature
36
Q
  1. Real gases show a minimum in the plot of Z versus pressure when the temperature is (A) Low (B) High (C) Constant (D) Zero
37
Q
  1. The volume effect in real gases accounts for (A) Positive deviation from ideal behavior (B) Negative deviation from ideal behavior (C) No deviation from ideal behavior (D) Ideal gas behavior
38
Q
  1. At high temperatures, the volume effect in real gases is (A) Less significant (B) More significant (C) Equal to the ideal gas law (D) Nonexistent
39
Q
  1. The negative deviation from ideal behavior occurs when (A) Molecules attract each other (B) Molecules are repelled (C) Temperature is extremely high (D) Gas molecules are far apart
40
Q
  1. At low temperatures, gas molecules are slowed down, causing (A) Increased intermolecular attraction (B) Decreased intermolecular attraction (C) No change in intermolecular forces (D) Increased molecular volume
41
Q
  1. The van der Waals equation attempts to modify the ideal gas equation by considering (A) Intermolecular attraction and molecular volume (B) Only molecular volume (C) Only intermolecular attraction (D) Ideal gas behavior
42
Q
  1. In the van der Waals equation, the correction for volume occupied by gas molecules is represented by (A) b (B) a (C) Z (D) RT
43
Q
  1. The excluded volume in the van der Waals equation is related to (A) The size of the molecules (B) The temperature of the gas (C) The number of moles of gas (D) The external pressure
44
Q
  1. The excluded volume for a pair of rigid spherical molecules is represented by (A) 4πr³/3 (B) 4πr² (C) 2πr³/3 (D) πr²
45
Q
  1. The correction for attractive forces in the van der Waals equation is proportional to (A) n²/V² (B) n/V (C) V/n (D) 1/n²
46
Q
  1. In the van der Waals equation, the term ‘a’ accounts for (A) Attractive forces among molecules (B) The volume occupied by molecules (C) The temperature of the gas (D) The molar volume
47
Q
  1. The van der Waals equation modifies the ideal gas law to account for (A) Real gas behavior (B) Increased temperature (C) Decreased pressure (D) Only molecular volume
48
Q
  1. The negative deviation from ideal gas behavior increases at (A) Low temperatures (B) High temperatures (C) High pressures (D) Low pressures
49
Q
  1. In the van der Waals equation, the term ‘b’ corrects for (A) The volume occupied by gas molecules (B) The molecular diameter (C) The intermolecular attractions (D) The temperature of the gas
50
Q
  1. What happens to real gas behavior at very high pressures? (A) The volume effect becomes significant (B) Gases behave ideally (C) There is no deviation from the ideal gas law (D) The intermolecular forces vanish
51
Q
  1. The attraction between gas molecules contributes to (A) Negative deviation from ideal behavior (B) Positive deviation from ideal behavior (C) Ideal gas behavior (D) No deviation
52
Q
  1. The van der Waals equation includes a term that accounts for (A) The internal pressure due to molecular attraction (B) The ideal gas constant (C) The molar volume (D) The temperature of the gas
53
Q
  1. Which of the following is a key assumption in the kinetic-molecular theory of gases? (A) Gas molecules have no volume (B) Molecules have significant volume (C) Molecules exert strong attraction on each other (D) Gas molecules move very slowly
54
Q
  1. The compressibility factor Z is defined as (A) PV/nRT (B) P/nRT (C) n/PVRT (D) RT/PV
55
Q
  1. At very low temperatures, gas molecules (A) Slow down and attract each other (B) Speed up and repel each other (C) Exhibit no intermolecular forces (D) Behave ideally
56
Q
  1. What does a compressibility factor of Z greater than 1 indicate? (A) Positive deviation from ideal gas behavior (B) Negative deviation from ideal gas behavior (C) Ideal gas behavior (D) No deviation from ideal gas behavior

CHM 112 (7 decks)

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