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What happens to the average speed of gas molecules as temperature increases?
What happens to the average speed of gas molecules as temperature increases?
Which gas will have the lowest average speed at a fixed temperature?
Which gas will have the lowest average speed at a fixed temperature?
In the van der Waals equation, what does the term 'a' correct for?
In the van der Waals equation, what does the term 'a' correct for?
Which gas is likely to resemble an ideal gas at lower temperatures?
Which gas is likely to resemble an ideal gas at lower temperatures?
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Which gas has the highest average kinetic energy at STP?
Which gas has the highest average kinetic energy at STP?
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What is the total pressure when carbon dioxide (PCO2) and water vapor (PH2O) are combined, given PT = (PCO2 + PH2O)?
What is the total pressure when carbon dioxide (PCO2) and water vapor (PH2O) are combined, given PT = (PCO2 + PH2O)?
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According to the ideal gas law, which of the following variables is directly proportional to the number of moles of a gas, assuming temperature and volume are constant?
According to the ideal gas law, which of the following variables is directly proportional to the number of moles of a gas, assuming temperature and volume are constant?
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What must be calculated first in order to find the volume of oxygen needed for the reaction involving 620 kg of ZnS?
What must be calculated first in order to find the volume of oxygen needed for the reaction involving 620 kg of ZnS?
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What is the relationship between the average kinetic energy of a gas and its absolute temperature according to Kinetic Molecular Theory?
What is the relationship between the average kinetic energy of a gas and its absolute temperature according to Kinetic Molecular Theory?
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Which of the following is a postulate of Kinetic Molecular Theory?
Which of the following is a postulate of Kinetic Molecular Theory?
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What is the approximate pressure of water vapor in a flask if 0.050 g of B4H10 burns completely, producing gaseous water in a 4.25-L container at 30.0 °C?
What is the approximate pressure of water vapor in a flask if 0.050 g of B4H10 burns completely, producing gaseous water in a 4.25-L container at 30.0 °C?
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Which of the following statements accurately describes non-ideal gas behavior?
Which of the following statements accurately describes non-ideal gas behavior?
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To solve for the mass of KClO3 used in the reaction that produces 386 mL of oxygen, which calculation is necessary first?
To solve for the mass of KClO3 used in the reaction that produces 386 mL of oxygen, which calculation is necessary first?
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Which equation represents the ideal gas law?
Which equation represents the ideal gas law?
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What is the function of the universal gas constant R in the ideal gas law?
What is the function of the universal gas constant R in the ideal gas law?
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Which gas law describes the direct relationship between volume and temperature?
Which gas law describes the direct relationship between volume and temperature?
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What happens to the pressure of a gas when its volume is decreased while keeping temperature constant?
What happens to the pressure of a gas when its volume is decreased while keeping temperature constant?
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Which of the following is a postulate of the kinetic theory of gases?
Which of the following is a postulate of the kinetic theory of gases?
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What is the initial pressure of a gas if its volume changes from 39 mL to 514 mL and the final pressure is 720 torr?
What is the initial pressure of a gas if its volume changes from 39 mL to 514 mL and the final pressure is 720 torr?
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In a mixture of gases, what term defines how each gas contributes to the total pressure?
In a mixture of gases, what term defines how each gas contributes to the total pressure?
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How does the density of gases generally compare to that of solids and liquids?
How does the density of gases generally compare to that of solids and liquids?
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How many moles of an ideal gas are present when the gas occupies a volume of 158 L at 14°C and a pressure of 89 kPa?
How many moles of an ideal gas are present when the gas occupies a volume of 158 L at 14°C and a pressure of 89 kPa?
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What is the total pressure in a flask containing H2O and O2 if the partial pressures are 0.42 atm for H2O and 0.21 atm for O2?
What is the total pressure in a flask containing H2O and O2 if the partial pressures are 0.42 atm for H2O and 0.21 atm for O2?
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If a gas behaves ideally, what is the relationship between temperature, volume, and pressure described by the ideal gas law?
If a gas behaves ideally, what is the relationship between temperature, volume, and pressure described by the ideal gas law?
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At standard temperature and pressure (STP), which of the following gases will occupy the greatest volume when given 2.0 g of each?
At standard temperature and pressure (STP), which of the following gases will occupy the greatest volume when given 2.0 g of each?
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Which law states that the total pressure of a gas mixture is equal to the sum of the partial pressures of its components?
Which law states that the total pressure of a gas mixture is equal to the sum of the partial pressures of its components?
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How is the mole fraction of a gas in a mixture calculated?
How is the mole fraction of a gas in a mixture calculated?
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For a gas sample containing 259 moles of CO2 and 513 moles of water, what is the partial pressure of CO2 if the total pressure is 21 atm?
For a gas sample containing 259 moles of CO2 and 513 moles of water, what is the partial pressure of CO2 if the total pressure is 21 atm?
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What is the standard molar volume of an ideal gas at standard temperature and pressure (STP)?
What is the standard molar volume of an ideal gas at standard temperature and pressure (STP)?
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Study Notes
Chapter 5: Gases
- Gases expand to fill any container they are placed in.
- Gases mix readily and thoroughly with each other.
- Gas volume changes greatly with varying temperatures.
- Gases have variable densities dependent on conditions.
- Gases have much lower densities than solids or liquids.
Chapter 5 Objectives
- Use the ideal gas law to calculate changes in gas conditions.
- Apply the concept of partial pressure to analyze gas mixtures.
- Calculate stoichiometric values for reactions involving gases.
- State the postulates of the kinetic theory of gases (KMT).
- Explain how the kinetic theory explains the behavior of gases.
- Distinguish between ideal and real gases.
Properties of Gases
- Gas pressure results from molecular collisions between gas molecules and container walls.
- Each collision imparts a small amount of force.
- The total force of these collisions produces macroscopic pressure.
- Pressure is measured using a barometer, where the height of the mercury column is proportional to atmospheric pressure.
- 1 torr = 1 mm Hg, 1 atm = 760 torr.
The Ideal Gas Law
- PV = nRT, where:
- P = pressure
- V = volume
- n = moles of gas
- R = ideal gas constant (0.08206 L atm mol⁻¹ K⁻¹)
- T = absolute temperature (in Kelvin)
- Moles = mass/molar mass
The Gas Laws
- Charles's Law: V ∝ T
- Boyle's Law: V ∝ 1/P
- Avogadro's Law: V ∝ n
- The ideal gas law combines these empirical gas laws.
Charles's Law
- Jacques Charles studied the relationship between volume (V) and temperature (T)
- Plots of V vs T for different gases converge to the same temperature at zero volume (absolute zero ≈-273°C).
Example Problems (Illustrative, not exhaustive)
- Problem solving examples provided on pages 9, 10, 11, 12, 19, 21, 22, 23. This involves applications of the gas laws, like Boyle’s law, Charles’ law and the ideal gas law.
Kinetic Molecular Theory (KMT)
- Gases are composed of tiny particles in constant, random motion.
- Gas particles have negligible volume compared to the container volume.
- Collisions between gas particles and container walls are elastic (no energy loss).
- Gas particles exert no significant attractive or repulsive forces on each other except during collisions.
- The average kinetic energy of gas particles is proportional to the absolute temperature.
Postulates of the Model
- Gases consist of large collections of particles moving randomly.
- Gas particles are very small and occupy negligible volume.
- Gas collisions with the container walls are elastic, conserving kinetic energy.
- Gas particles interact with each other only during collisions.
- Average kinetic energy is proportional to temperature, regardless of particle identity.
- As temperature rises, average speed increases.
- At a given temperature, heavier particles move slower on average than lighter particles.
Limitations of KMT
- At high pressure, particle volume becomes significant.
- At low temperatures, intermolecular forces become important.
Correcting the Ideal Gas Equation
- The van der Waals equation accounts for particle volume and intermolecular forces:
- (P+an2V2)(V−nb)=nRT(P + \frac{an^2}{V^2})(V - nb) = nRT(P+V2an2)(V−nb)=nRT
- a corrects for intermolecular attractions
- b corrects for particle volume
Partial Pressure
- Dalton's Law of Partial Pressures: The total pressure of a mixture of gases is the sum of the partial pressures of the individual gases.
- Partial pressure depends on the mole fraction of each gas.
- Mole fraction (Xᵢ) = (moles of gas i) / (total moles of gas).
Stoichiometry of Reactions Involving Gases
- Ideal gas law (PV=nRT) is often used to solve gas stoichiometry problems by relating moles of gas to pressure, volume, or temperature.
Additional Notes
- Real gases deviate from ideal gas behavior under high pressure and low temperature. Ideal gases are a simplified model.
- The provided pages contain various example problems applying gas laws to determine different properties, including volume, pressure, moles, and mass.
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Description
Explore the fascinating properties and behaviors of gases in this quiz based on Chemistry Chapter 5. Understand key concepts such as the ideal gas law, partial pressure, and the kinetic theory of gases. Test your knowledge on how gases behave under different conditions.
