The line labeled "Raoult's law" represents ideality. For systems that obey this law, the activity coefficients of both A and B are unity over the entire composition range. The equilibrium partial pressures are lower than the pure-component vapor pressures by factors exactly equal to the corresponding mole fraction in the ideal solution:

Such solutions are the exception rather than the rule. For Raoult's law to be followed, the two components must be chemically very similar (e.g., A = benzene and B = toluene - see problem 8.1). However, even metals as similar as nickel and iron exhibit nonideal behavior when alloyed.

In Fig. 8.2, the partial pressure curve joins the Raoult's law line well before xA reaches one. That is, not only is yA ^ 1 as xA ^ 1, but dyA/dxA ^ 0 as well.

Solar Panel Basics

Solar Panel Basics

Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.

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