Q. A gas at 300 K has an RMS speed of 400 m/s. What will be its RMS speed at 600 K?
A.400 m/s
B.400 sqrt(2) m/s
C.800 m/s
D.200 m/s
Solution
The RMS speed is proportional to the square root of the temperature. Therefore, at 600 K, the RMS speed will be 400 * sqrt(600/300) = 400 * sqrt(2) m/s.
Q. A gas has an RMS speed of 500 m/s. If the molar mass of the gas is 0.02 kg/mol, what is the temperature of the gas?
A.250 K
B.500 K
C.1000 K
D.2000 K
Solution
Using the formula v_rms = sqrt((3RT)/M), we can rearrange to find T = (v_rms^2 * M) / (3R). Substituting v_rms = 500 m/s and M = 0.02 kg/mol gives T = 500 K.
Q. For a gas at a constant temperature, if the molar mass is halved, what happens to the RMS speed?
A.Increases by a factor of sqrt(2)
B.Increases by a factor of 2
C.Decreases by a factor of 2
D.Remains the same
Solution
The RMS speed is inversely proportional to the square root of the molar mass. If the molar mass is halved, the RMS speed increases by a factor of sqrt(2), which is approximately 1.414, but in terms of doubling the speed, it is considered to increase by a factor of 2.
Q. For a gas with molar mass M, what is the relationship between RMS speed and molar mass?
A.v_rms is directly proportional to M
B.v_rms is inversely proportional to M
C.v_rms is independent of M
D.v_rms is proportional to M^2
Solution
The RMS speed is inversely proportional to the square root of the molar mass (v_rms = sqrt((3RT)/M)). Thus, as molar mass increases, RMS speed decreases.
Correct Answer: B — v_rms is inversely proportional to M
Q. For a gas with molar mass M, what is the relationship between RMS speed and molecular mass?
A.v_rms is directly proportional to M
B.v_rms is inversely proportional to M
C.v_rms is independent of M
D.v_rms is proportional to M^2
Solution
The RMS speed is inversely proportional to the square root of the molar mass (v_rms = sqrt((3RT)/M)). Thus, as molar mass increases, RMS speed decreases.
Correct Answer: B — v_rms is inversely proportional to M
Q. If the molar mass of a gas is halved, what happens to its RMS speed?
A.Increases by a factor of sqrt(2)
B.Increases by a factor of 2
C.Decreases by a factor of sqrt(2)
D.Remains the same
Solution
If the molar mass is halved, the RMS speed increases by a factor of sqrt(2) because RMS speed is inversely proportional to the square root of molar mass.
Correct Answer: A — Increases by a factor of sqrt(2)
Q. If the RMS speed of a gas is 300 m/s, what is the RMS speed of the same gas at double the temperature?
A.300 m/s
B.600 m/s
C.300√2 m/s
D.600√2 m/s
Solution
The RMS speed is proportional to the square root of the temperature. If the temperature is doubled, the RMS speed increases by a factor of sqrt(2). Therefore, the new RMS speed will be 300 * sqrt(2), which is approximately 600 m/s.
Q. If the RMS speed of a gas is 400 m/s and its molar mass is 16 g/mol, what is the temperature of the gas?
A.200 K
B.400 K
C.800 K
D.1600 K
Solution
Using the formula v_rms = sqrt((3RT)/M), we can rearrange to find T: T = (M * v_rms^2) / (3R). Substituting M = 0.016 kg/mol and v_rms = 400 m/s gives T = 400 K.