A sample of \(n\) moles of an ideal gas undergoes an isothermal expansion. Find the heat flow into the gas in terms of the initial and final volumes and the temperature.

Short Answer

Expert verified
The heat flow into the gas during an isothermal expansion is given by \(Q = nRT \ln(V_f/V_i)\)

Step by step solution

01

Isothermal process condition

For the gas to undergo isothermal expansion, it must maintain a constant temperature throughout the process. Hence, \(T = constant\).
02

Calculate work done in an isothermal process

In an isothermal process of an ideal gas, the work done \(W\) is given by the formula \(W = nRT \ln(V_f/V_i)\), where \(V_f\) is the final volume and \(V_i\) is the initial volume. Since this is a logarithmic equation, make sure that the volume values are in the same units before plugging them in.
03

Determine heat flow

In an isothermal process, the heat flow \(Q\) into the gas is equal to the work done by the gas, i.e., \(Q = W\). Therefore, substituting the value of \(W\) from Step 2 we get \(Q = nRT \ln(V_f/V_i)\).

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