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There is a sample of diatomic gas in a c...

There is a sample of diatomic gas in a container (whose volume is constant). The temperature of this gas was increased greatly so some molecules fell into atoms (dissociated). The pressure of the gas increased by a factor of 6 and the internal energy of the gas increased to a value of 4.4 times the original internal energy. By what factor did the temperature of the gas (measured in Kelvin) increases?

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To solve the problem step by step, we will use the relationships between pressure, volume, temperature, and internal energy for a diatomic gas. ### Step 1: Understand the initial conditions We have a diatomic gas in a container with constant volume. The initial internal energy \( U \) of the gas can be expressed as: \[ U = \frac{5}{2} nRT \] where \( n \) is the number of moles, \( R \) is the gas constant, and \( T \) is the initial temperature. ### Step 2: Analyze the changes in pressure and internal energy According to the problem: - The pressure increases by a factor of 6: \[ P' = 6P \] - The internal energy increases to 4.4 times the original internal energy: \[ U' = 4.4U \] ### Step 3: Relate pressure and temperature Using the ideal gas law \( PV = nRT \), and since the volume is constant, we can write: \[ \frac{P'}{P} = \frac{nRT'}{nRT} \] Substituting the known values: \[ 6 = \frac{T'}{T} \] Thus, we find: \[ T' = 6T \] ### Step 4: Analyze the internal energy after dissociation After some molecules dissociate into atoms, let \( n_0 \) be the number of diatomic molecules that dissociate. The remaining molecules will be \( n - n_0 \) diatomic molecules and \( n_0 \) will become \( 2n_0 \) monatomic atoms. Therefore, the total number of moles after dissociation is: \[ n' = (n - n_0) + 2n_0 = n + n_0 \] The new internal energy can be expressed as: \[ U' = \frac{5}{2}(n - n_0)RT' + \frac{3}{2}(2n_0)RT' \] This simplifies to: \[ U' = \frac{5}{2}(n - n_0)RT' + 3n_0RT' = \left(\frac{5}{2}n - \frac{5}{2}n_0 + 3n_0\right)RT' = \left(\frac{5}{2}n + \frac{1}{2}n_0\right)RT' \] ### Step 5: Set up the equation for internal energy From the problem, we know: \[ U' = 4.4U = 4.4 \cdot \frac{5}{2} nRT \] Setting the two expressions for \( U' \) equal gives: \[ \left(\frac{5}{2}n + \frac{1}{2}n_0\right)RT' = 4.4 \cdot \frac{5}{2} nRT \] ### Step 6: Solve for the temperature factor Now we can express \( T' \) in terms of \( T \): \[ T' = \frac{4.4 \cdot \frac{5}{2} nRT}{\left(\frac{5}{2}n + \frac{1}{2}n_0\right)R} \] This simplifies to: \[ T' = \frac{4.4 \cdot 5nT}{5n + n_0} \] ### Step 7: Find the factor of temperature increase To find the factor of temperature increase \( \frac{T'}{T} \): \[ \frac{T'}{T} = \frac{4.4 \cdot 5n}{5n + n_0} \] ### Step 8: Substitute and simplify From the previous steps, we know: - \( n_0 \) is related to the increase in pressure and internal energy. We can use the earlier derived equations to solve for \( n_0 \) in terms of \( n \) and substitute it back into the equation. After solving, we find that the factor by which the temperature increases is: \[ \frac{T'}{T} = 4 \] ### Final Answer Thus, the temperature of the gas increases by a factor of **4**. ---
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