Mixtures are used in various places around the world. Solder is one of them. Solder is a mixture of lead (Pb) and (Sn), which is melted with a heating tool called a soldering iron. , the parts are fixed (remember those who practiced soldering in technology class when they were junior high school students). Figure 2 shows the phase relationship of the pl-Sn system. The reason why a mixture of Pb and Sn is used instead of single Pb or single Sn is that this lowers the melting point and makes it easier for solder to touch. I want to think about it.

Assuming that the Pb-Sn interaction coefficient in the solid solution  is 4000, find the activity and chemical potential of the pb component in the solid solution. Find the activity of the PD component in the resulting liquid.

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por 3 . ). . PbSn (1)(9). 2. PbSn (1 ). Pb Sn Sn (6) Pb-Sn 4000 (2) Pb . ( 3 ) (3 )