48. Solution to Chemistry Problem

6. Using the data from Table 1, construct a melting diagram for the beryllium-silicon system.
Table 1
Be,
% by weight 0 20 40 61 80 100
Tn, С 1282 1205 1151 1100 1215 1402
Tk, С 1282 1100 1100 1100 1100 1402

Where Tn is the temperature at which crystallization begins; Tk is the temperature at which crystallization ends.
Using the diagram for the 75% by weight Si alloy, determine:
1. Temperatures at which crystallization begins and ends;
2. Composition of the first crystal and the last drop of liquid;
3. Mass of silicon in the solid and liquid states upon cooling 0.8 kg of the alloy to a temperature of 1150 С.
On the diagram, mark all areas and lines, give the diagram a full title. Mark with dots the melt containing 15% by weight of silicon, which is in equilibrium with solid beryllium. Determine the number of degrees of freedom at a given point.