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===== Homework Tips ===== | ===== Homework Tips ===== | ||

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+ | ==== Average Spacing of Gas Molecules ===== | ||

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+ | Use $PV=nkT$ with $n=1$. Don't forget to convert the pressure and temperature to the right units! | ||

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+ | ==== Problem 19.13 ==== | ||

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+ | To solve this problem we need to consider the specific heat of water and glass. We then need to write an equation for the total heat transfer in the system, which should be zero. | ||

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+ | ==== Problem 19.61 ==== | ||

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+ | A radiative heat transfer problem. To work out the temperature change approximate that all the heat is coming from the water and that the rate of heat output does not change during the cooling. | ||

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+ | ==== Problem 19.72 ==== | ||

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+ | A heat conduction problem. | ||

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+ | ==== Problem 19.36 ==== | ||

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+ | This problem involves the latent heat of vaporization of water (2260kJ/kg) and the first law of thermodynamics for an isobaric process. | ||

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+ | To find $\Delta V$ you will need to consider the steam as an ideal gas, as we did when deriving the molar specific heat of an ideal gas at constant pressure. | ||

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+ | Remember that the molecular mass of water is 18 g/mol. | ||

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+ | ==== Problem 19.43 ==== | ||

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+ | As we saw from the equipartition theorem an ideal diatomic gas should have a constant volume molar heat capacity of $c_{V,m}=\frac{5}{2}R$. Is this process constant volume or constant pressure? | ||

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+ | Once you have decided on the appropriate molar heat capacity you will need to determine the number moles of gas. You can do this using the ideal gas law $PV=nRT$. | ||

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+ | ==== Problem 19.54 ==== | ||

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+ | You will need to use the result we obtained that for the quasistatic adiabatic expansion of an ideal gas that $PV^{\gamma}=\mathrm{constant}$ and that for any ideal gas $PV=nRT$. | ||