Which of the following statements is not true?a)The ratio of the mean ...
According to Kinetic Molecular Theory, an increase in temperature will increase the average kinetic energy of the molecules. As the particles move faster, they will likely hit the edge of the container more often. If the reaction is kept at constant pressure, they must stay farther apart, and an increase in volume will compensate for the increase in particle collision with the surface of the container.
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Which of the following statements is not true?a)The ratio of the mean ...
Explanation:
The statement that is not true is option B, which states that the square of the mean speed of the molecules is equal to the mean squared speed at a certain temperature. Let's break down each statement to understand why option B is incorrect.
a) The ratio of the mean speed to the rms speed is independent of the temperature:
- The mean speed of gas molecules is calculated by summing up the speeds of all the molecules and dividing by the total number of molecules.
- The root mean square (rms) speed is calculated by taking the square root of the average of the squares of the speeds of all the molecules.
- The ratio of the mean speed to the rms speed is √3/1, which is a constant value and independent of temperature. This ratio remains the same for all gases at any given temperature.
b) The square of the mean speed of the molecules is equal to the mean squared speed at a certain temperature:
- This statement is not true. The mean speed of gas molecules is given by the expression √8RT/πM, where R is the gas constant, T is the temperature, and M is the molar mass of the gas.
- The mean squared speed is given by the expression 3RT/M.
- The square of the mean speed (√8RT/πM)^2 is not equal to the mean squared speed (3RT/M) at any temperature. They have different mathematical expressions and values.
c) Mean kinetic energy of the gas molecules at any given temperature is independent of the mean speed:
- The mean kinetic energy of gas molecules is given by the expression 3/2 kT, where k is the Boltzmann constant and T is the temperature.
- The mean kinetic energy is independent of the mean speed. It depends only on the temperature and not on the mean speed of the gas molecules.
d) The difference between rms speed and mean speed at any temperature for different gases diminishes as larger molar masses are considered:
- This statement is true. As the molar mass of a gas increases, the difference between the rms speed and mean speed decreases.
- This can be understood by considering the formula for rms speed, which is √(3RT/M), and the formula for mean speed, which is √(8RT/πM).
- As the molar mass increases, the denominator in both formulas increases, leading to a decrease in both the rms speed and mean speed. However, the decrease is more significant for the mean speed, resulting in a smaller difference between the two speeds.
In conclusion, the statement that is not true is option B, which states that the square of the mean speed of the molecules is equal to the mean squared speed at a certain temperature.
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