Ⅱ. At T 1℃, the solubility of A is 25g, and the saturated solution of 125g contains 25g of A; the saturated solution of 100g contains 25g× 100g = 20g, and the solute mass fraction of this solution is 2065438+.
The solubility of ⅲ.A increases with the increase of temperature, so the saturated solution can be transformed into unsaturated solution with the increase of temperature.
Ⅳ. At t 1℃, the solubility of Party A and Party B is 25g, that of 100g water is 25g, and that of 20g water is 5g. At T 1℃, beakers A and B are both filled with 20g of water, and two substances A and B with equal mass are added respectively. After stirring, solid remains, so the added solid mass must be greater than 5g;
ⅴ. When the solution in two beakers is heated to t2℃, the solubility of A increases with the increase of temperature, and no crystals are precipitated, and the solution changes from saturation to unsaturation, and the solute mass becomes larger, while the solvent remains unchanged, and the solution mass becomes larger; The solubility of B decreases with the increase of temperature, and crystals are precipitated, so the mass of solute becomes smaller, the solvent remains unchanged, and the mass of solution becomes smaller.
Answer:
I at t1℃, the solubility of a and b is the same.
Ⅱ.20 20%
ⅲ.A.
Ⅳ.5
Ⅴ.②④