Multiple Choice
The system volume is 10 L at STP. If the temperature decreases to 30 K, what is the new volume, assuming pressure remains constant?
7. Gases
The Ideal Gas Law
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Which of the following statements is true about a molecule of gaseous hydrogen (H2) under ideal gas conditions?
A
The volume of the H2 molecule is negligible compared to the volume of the container.
B
The average kinetic energy of H2 molecules is the same at all temperatures.
C
The pressure of H2 is independent of temperature.
D
The H2 molecules attract each other significantly.
Verified step by step guidance1
Identify the key characteristics of an ideal gas. Ideal gases are theoretical gases composed of many randomly moving point particles that interact only through elastic collisions.
Recall that under ideal gas conditions, the volume of individual gas molecules is considered negligible compared to the volume of the container. This is because the gas molecules are assumed to be point particles with no volume.
Understand that the average kinetic energy of gas molecules is directly proportional to the temperature in Kelvin. Therefore, the average kinetic energy of H2 molecules changes with temperature.
Recognize that the pressure of an ideal gas is dependent on temperature, as described by the ideal gas law: \( PV = nRT \), where \( P \) is pressure, \( V \) is volume, \( n \) is the number of moles, \( R \) is the ideal gas constant, and \( T \) is temperature.
Note that ideal gas molecules do not attract or repel each other significantly. They are assumed to have no intermolecular forces, which is why the statement about H2 molecules attracting each other significantly is false under ideal gas conditions.
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